Two speed trailer jack

ABSTRACT

A linear jack includes a first outer sleeve, an inner sleeve disposed at least partially within the first outer sleeve, a second outer sleeve disposed at least partially within the inner sleeve, a translating screw disposed at least partially within the second outer sleeve, and a cover sleeve coupled to the translating screw. The first outer sleeve is threadedly coupled to the inner sleeve. The second outer sleeve is threadedly coupled to the translating screw. The translating screw is disposed at least partially within the cover sleeve. The cover sleeve is configured to translate with the translating screw.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims priority to, the benefit of, and is acontinuation-in-part of U.S. patent application Ser. No. 16/943,997,filed on Jul. 30, 2020, and entitled “TWO SPEED TRAILER JACK,” whichclaims priority to, the benefit of, and is a continuation-in-part ofU.S. patent application Ser. No. 16/883,811, filed on May 26, 2020, andentitled “TWO SPEED TRAILER JACK,” which are incorporated by referenceherein in their entirety for all purposes.

FIELD

The present disclosure relates generally to apparatuses such as jacksfor lifting and suspending vehicles, trailers, and other large objects,and, more specifically, to linear jacks that are used to selectivelylower and raise, for example, a portion of a trailer.

BACKGROUND

Many of the different types of trailers that are towed by trucks areconnected to the trucks by a releasable coupling such as a gooseneckcoupling, a fifth wheel coupling, a bumper pull coupling and the like.After the trailer is released from the truck and is no longer supportedby the truck at the forward end of the trailer, a lifting device, suchas a jack and/or landing gear assembly, is often used to support thetrailer floor or bed, typically in a position generally horizontal tothe ground.

A typical lifting device is attached to the trailer adjacent the truckcoupling at the forward end of the trailer. The lifting device includesone or more vertically oriented columns and a vertical leg is mounted onthe column. A hand crank is typically connected to the gear mechanism.Selectively rotating the hand crank lowers the leg until the legcontacts the ground and supports the forward end of the trailer when thetrailer is being uncoupled from the truck, or raises the leg when thetrailer has been connected to a truck and is ready for towing.

SUMMARY

A linear jack is disclosed, comprising a first sleeve, a second sleevedisposed at least partially within the first sleeve, wherein the firstsleeve is threadedly coupled to the second sleeve, a third sleevedisposed at least partially within the second sleeve, a translatingscrew disposed at least partially within the third sleeve, wherein thethird sleeve is threadedly coupled to the translating screw, and a coversleeve coupled to the translating screw. The translating screw isdisposed at least partially within the cover sleeve, and the coversleeve is configured to translate with the translating screw.

In various embodiments, the cover sleeve is disposed at least partiallywithin the second sleeve.

In various embodiments, the cover sleeve is keyed to the second sleeve.

In various embodiments, the second sleeve is configured to translatewith respect to the first sleeve in response to rotation of the firstsleeve, and the translating screw is configured to translate withrespect to the third sleeve in response to rotation of the third sleeve.

In various embodiments, a thread pitch of the second sleeve is greaterthan a thread pitch of the translating screw.

In various embodiments, the linear jack further comprises an outer tubecomprising a centerline axis, wherein the first sleeve is disposed atleast partially within the outer tube, a shaft coupled to the thirdsleeve, a gear coupled to the shaft, and a spring operatively coupled tothe first sleeve, wherein the first sleeve is slidable in the outer tubebetween a first position and a second position. In the first position,the spring biases the first sleeve to engage the gear whereby turningthe shaft a first rotational direction extends the second sleeve fromthe first sleeve, and turning the shaft a second rotational directionretracts the second sleeve into the first sleeve. In the secondposition, the first sleeve is moved against a bias of the spring anddisengaged from the gear whereby turning the shaft the first rotationaldirection extends the translating screw from the third sleeve, andturning the shaft the second rotational direction retracts thetranslating screw into the third sleeve.

In various embodiments, turning the shaft the first rotational directionextends the translating screw from the third sleeve, and turning theshaft the second rotational direction retracts the translating screwinto the third sleeve, regardless of the first sleeve being in the firstposition or the second position.

In various embodiments, the third sleeve is configured to rotate withthe shaft, the gear is disposed within the first sleeve, and the springis disposed within the outer tube.

In various embodiments, the first sleeve, the second sleeve, the thirdsleeve, and the translating screw are in coaxial alignment.

In various embodiments, the linear jack further comprises a foot coupledto an end of the translating screw.

A linear jack arrangement is disclosed, comprising a shaft, a firstsleeve configured to receive the shaft, a translating screw disposed atleast partially within the first sleeve, wherein the first sleeve isthreadedly coupled to the translating screw, wherein the shaft isconfigured to receive the translating screw.

In various embodiments, the first sleeve is configured to rotate inresponse to rotation of the shaft.

In various embodiments, the shaft, the first sleeve, and the translatingscrew are coaxially aligned.

In various embodiments, the linear jack arrangement further comprises asecond sleeve, wherein the first sleeve is disposed within the secondsleeve.

In various embodiments, the second sleeve comprises a first flange and asecond flange, wherein the first flange extends radially inward from thesecond sleeve and the second flange extends radially inward from thesecond sleeve.

In various embodiments, the first sleeve comprises a third flangeextending radially outward therefrom, wherein the third flange isdisposed axially between the first flange and the second flange.

In various embodiments, the first sleeve comprises a flange extendingradially inward therefrom, wherein the first sleeve is threadedlycoupled to the translating screw via the flange.

In various embodiments, the linear jack arrangement further comprises acover sleeve coupled to the translating screw, wherein the translatingscrew is disposed at least partially within the cover sleeve.

A method of manufacturing a linear jack is disclosed, comprisingdisposing a second sleeve at least partially within a first sleeve,wherein the first sleeve is threadedly coupled to the second sleeve,disposing a translating screw at least partially within a third sleeve,wherein the third sleeve is threadedly coupled to the translating screw,disposing the third sleeve at least partially within the second sleeve,and coupling a cover sleeve to the translating screw, wherein the coversleeve is configured to translate with the translating screw.

In various embodiments, the method further comprises disposing the coversleeve to surround the translating screw, disposing the cover sleeve tosurround the third sleeve, and disposing the cover sleeve in keyedconnection with the second sleeve.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. It should be understood, however, the following descriptionand drawings are intended to be example in nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

The subject matter of the present disclosure is particularly pointed outand distinctly claimed in the concluding portion of the specification. Amore complete understanding of the present disclosure, however, may bestbe obtained by referring to the detailed description and claims whenconsidered in connection with the figures, wherein like numerals denotelike elements.

FIG. 1 illustrates a schematic view of a trailer-mounted lifting devicesupporting a front end of a trailer on a ground surface, in accordancewith various embodiments.

FIG. 2 illustrates an exploded view of a lifting device, in accordancewith various embodiments.

FIG. 3A and FIG. 3B illustrate a partially exploded view of a low speedassembly and a shaft of the lifting device of FIG. 2, the shaft fordriving the low speed assembly, in accordance with various embodiments.

FIG. 4A and FIG. 4B illustrate a side view and a section view,respectively, of the lifting device of FIG. 2, with the lifting devicein a retracted state, and a high speed sleeve in a first position, inaccordance with various embodiments.

FIG. 4C and FIG. 4D illustrate a side view and a section view,respectively, of the lifting device of FIG. 4A and FIG. 4B, with thelifting device in a partially extended state, and the high speed sleevein the first position, in accordance with various embodiments.

FIG. 4E and FIG. 4F illustrate a side view and a section view,respectively, of the lifting device of FIG. 4A and FIG. 4B, with thelifting device in an extended state, and the high speed sleeve in asecond position, in accordance with various embodiments.

FIG. 5A and FIG. 5B illustrate a side view and a section view,respectively, of the lifting device of FIG. 4A and FIG. 4B, with anouter tube of the lifting device omitted for clarity purposes, inaccordance with various embodiments.

FIG. 6A and FIG. 6B illustrate a side view and a section view,respectively, of the lifting device of FIG. 4A and FIG. 4B, with theouter tube and the high speed sleeve of the lifting device omitted forclarity purposes, in accordance with various embodiments.

FIG. 7A and FIG. 7B illustrate a side view and a section view,respectively, of the high speed sleeve of FIG. 2, in accordance withvarious embodiments.

FIG. 8A and FIG. 8B illustrate a side view and a section view,respectively, of a partially exploded view of the low speed assembly ofthe lifting device of FIG. 2, in accordance with various embodiments.

FIG. 9A, FIG. 9B, and FIG. 9C illustrate a side view, a section view,and a perspective view, respectively, of the low speed sleeve of FIG. 2,in accordance with various embodiments.

FIG. 10A and FIG. 10B illustrate a perspective view and a side view,respectively, of a lifting device comprising an attachment feature, inaccordance with various embodiments.

FIG. 11A and FIG. 11B illustrate a section view and a perspective view,respectively, of an outer tube of a lifting device comprising anattachment feature for attaching the lifting device to a trailer, inaccordance with various embodiments.

FIG. 12 illustrates a landing gear assembly having two lifting devices,in accordance with various embodiments.

FIG. 13A and FIG. 13B illustrate a lifting device for the landing gearassembly of FIG. 12 with an sleeve of the lifting device in a firstposition and a second position, respectively, and comprising a shaftdriven by a crank with the outer tube removed for clarity purposes, inaccordance with various embodiments.

FIG. 14 illustrates a section view of one of the lifting devices of FIG.12, in accordance with various embodiments.

FIG. 15A and FIG. 15B illustrate a section view and a side view,respectively, of a lifting device comprising a low speed assemblycomprising a rotating screw and a translating nut, in accordance withvarious embodiments.

FIG. 16 illustrates an exploded view of a lifting device comprising ahigh speed assembly nested within a low speed assembly, in accordancewith various embodiments.

FIG. 17A and FIG. 17B illustrate a side view and a section view,respectively, of the lifting device of FIG. 16, with the lifting devicein a retracted state, and a high speed rotating screw in a firstposition, in accordance with various embodiments.

FIG. 17C and FIG. 17D illustrate a side view and a section view,respectively, of the lifting device of FIG. 17A and FIG. 17B, with thelifting device in an extended state, and the high speed rotating screwin a second position, in accordance with various embodiments.

FIG. 18 illustrates a flow chart of a method of manufacturing a liftingdevice, in accordance with various embodiments.

FIG. 19A and FIG. 19B illustrate a side view and a section view,respectively, of a lifting device comprising a first jack screw assemblyincluding a thread pitch that is equal to a second jack screw assembly,in accordance with various embodiments.

FIG. 20 illustrates an exploded view of a lifting device comprising aplanetary gear system, in accordance with various embodiments.

FIG. 21A and FIG. 21B illustrate a side view and a section view,respectively, of the lifting device of FIG. 20, with the lifting devicein a retracted state, and an sleeve in a first position and a sun gearin a first position, in accordance with various embodiments.

FIG. 21C and FIG. 21D illustrate a side view and a section view,respectively, of the lifting device of FIG. 21A and FIG. 21B, with thelifting device in an extended state, and the sleeve in a second positionand a sun gear in a second position, in accordance with variousembodiments.

FIG. 22 illustrates an exploded view of a lifting device, in accordancewith various embodiments.

FIG. 23A illustrates a section view of the lifting device of FIG. 22,with the lifting device in a retracted state, and an sleeve in a firstposition, in accordance with various embodiments.

FIG. 23B and FIG. 23C illustrate a side view and a section view,respectively, of the lifting device of FIG. 23A, with the lifting devicein an extended state, in accordance with various embodiments.

FIG. 23D and FIG. 23E illustrate the lifting device of FIG. 22 with thesleeve in a first position and a second position, respectively, inaccordance with various embodiments.

FIG. 24A and FIG. 24B illustrate a swiveling foot of the lifting deviceof FIG. 22, respectively, in accordance with various embodiments.

FIG. 25 illustrates an exploded view of a two-piece telescoping shaftfor a lifting device, in accordance with various embodiments.

FIG. 26A and FIG. 26B illustrate a section view and a side view,respectively of a lifting device in a retracted state and having thetwo-piece telescoping shaft of FIG. 25, in accordance with variousembodiments.

FIG. 26C and FIG. 26D illustrate a section view and a side view,respectively of the lifting device of FIG. 26A and FIG. 26B in a fullyextended state and having the two-piece telescoping shaft of FIG. 25, inaccordance with various embodiments.

FIG. 27 illustrates a flow chart of a method of assembling a liftingdevice, in accordance with various embodiments.

FIG. 28A and FIG. 28B illustrate a side view and a section view,respectively, of a lifting device in a retracted state, and a high speedsleeve in a first position, in accordance with various embodiments.

FIG. 28C and FIG. 28D illustrate a side view and a section view,respectively, of the lifting device of FIG. 28A and FIG. 28B, with thelifting device in an extended state, and the high speed sleeve in asecond position, in accordance with various embodiments.

FIG. 29A illustrates a section view of an upper portion of the liftingdevice of FIG. 28B, in accordance with various embodiments.

FIG. 29B illustrates a section view of a lower portion of the liftingdevice of FIG. 28B, in accordance with various embodiments.

FIG. 30 illustrates a section view of the lower portion of the liftingdevice of FIG. 28B, with the outer tube and the high speed assemblyomitted, in accordance with various embodiments.

FIG. 31 illustrates a flow chart of a method of assembling a liftingdevice, in accordance with various embodiments.

DETAILED DESCRIPTION

All ranges and ratio limits disclosed herein may be combined. It is tobe understood that unless specifically stated otherwise, references to“a,” “an,” and/or “the” may include one or more than one and thatreference to an item in the singular may also include the item in theplural.

The detailed description of various embodiments herein makes referenceto the accompanying drawings, which show various embodiments by way ofillustration. While these various embodiments are described insufficient detail to enable those skilled in the art to practice thedisclosure, it should be understood that other embodiments may berealized and that logical, chemical, and mechanical changes may be madewithout departing from the spirit and scope of the disclosure. Thus, thedetailed description herein is presented for purposes of illustrationonly and not of limitation. For example, the steps recited in any of themethod or process descriptions may be executed in any order and are notnecessarily limited to the order presented. Furthermore, any referenceto singular includes plural embodiments, and any reference to more thanone component or step may include a singular embodiment or step. Also,any reference to attached, fixed, connected, or the like may includepermanent, removable, temporary, partial, full, and/or any otherpossible attachment option. Additionally, any reference to withoutcontact (or similar phrases) may also include reduced contact or minimalcontact. Cross hatching lines may be used throughout the figures todenote different parts but not necessarily to denote the same ordifferent materials.

Typical lifting devices, such as linear trailer jacks, operate using aconstant thread pitch sized to obtain sufficient mechanical advantage tolift a heavy load, such as a trailer. In that regard, as a smallerthread pitch increases mechanical advantage relative to a larger threadpitch, many available linear trailer jacks use a constant, small threadpitch. However, the gain in mechanical advantage is offset by theincrease in the number of rotations of an input device (e.g., a handle)needed to extend (translate) the linear trailer j ack. In this manner,conventional linear trailer jack may provide the mechanical advantagedesired to lift a trailer but at the expense of time consuming, andbothersome, turning.

Thread pitch, as used herein, is generally defined as the distancebetween threads on a threaded coupling, such as that found on a screw,lead screw or jack screw. Thread count, expressed for example as threadsper inch, is generally defined as the number of threads per inch oflinear distance on a threaded coupling, such as that found on a screw,lead screw or jack screw. In that regard, thread pitch and thread countare related, both expressing the spacing of threads about a screw, leadscrew or jack screw.

Systems and methods for a two speed lifting device—such as a lineartrailer jack—are provided herein. A lifting device of the presentdisclosure generally comprises a high speed assembly and a low speedassembly. The high speed assembly generally comprises a screw mechanismcomprising a nut threadedly coupled to a screw. In various embodiments,the nut rotates and the screw translates, and in various embodiments,the nut translates and the screw rotates. The screw and nut arethreadedly coupled for translating the rotational force to a linearforce. The low speed assembly also comprises a nut threadedly coupled toa screw. A thread pitch of the high speed assembly is greater than athread pitch of the low speed assembly, in various embodiments. In thismanner, when driven by a common shaft and/or at the same revolutions perunit time, the high speed assembly causes the lifting device to extend agreater linear distance per rotation of a shaft than the low speedassembly.

In this manner, the high speed assembly causes more linear extension perrotation and thus reduces the number of rotations needed to lower orraise the lifting device. This reduces or eliminates the wasted timeincurred if no such high speed assembly existed. However, when thelifting device begins to touch the ground, and mechanical advantage nowbecomes more important, in various embodiments, the high speed assemblyis disengaged, for example, automatically disengaged. Thus, in responseto the lifting device contacting a ground surface, a force is reactedinto the high speed assembly, thereby moving a moveable member of thehigh speed assembly from a first position to a second position, anddisengaging the high speed assembly from being drivably coupled with theshaft and/or other motive rotational force. With the moveable member ofthe high speed assembly in the second position, only the low speedassembly is driven in response to rotation of the shaft, therebybenefiting from the mechanical advantage of the low speed assembly,which has a smaller thread pitch than the high speed assembly. In thismanner, lifting devices of the present disclosure may quickly andefficiently extend in overall length, reducing the number of turnsrequired to reach a ground surface, while still providing the mechanicaladvantage to lift heavy loads. In various embodiments, this transitionoccurs without any additional action and thus improves ease of use andreduces overall time needed for operation. In this manner, liftingdevices of the present disclosure may automatically switch from a highspeed mode to a low speed mode in response to the ground force beingreacted through the lifting device (i.e., in response to contacting theground as the jack is extended).

With reference to FIG. 1, a trailer 120 partially supported on a groundsurface 190 by a lifting device 100 is illustrated, in accordance withvarious embodiments. Lifting device 100 may be coupled to a front end ofthe trailer 120. Lifting device 100 may be generally vertically orientedwhen supporting the front end of the trailer 120. Although illustratedcoupled to a utility type trailer, lifting devices of the presentdisclosure may be utilized on any trailer or vehicle where support isdesired, for example, with a camper, recreational vehicle, toy hauler,boat, or any other device capable of being towed as a trailer.

With reference to FIG. 2, an exploded view of a lifting device 200 isillustrated, in accordance with various embodiments. Lifting device 200may be a linear jack. Lifting device 200 may generally comprise an outertube 210, a high speed assembly 202, and a low speed assembly 204. Highspeed assembly 202 may generally comprise a screw mechanism comprising arotating nut threadedly coupled to a translating screw, in the manner ofa leadscrew or jack screw. In various embodiments, high speed assembly202 comprises a rotating first sleeve 220 (also referred to herein as ahigh speed outer sleeve or a first sleeve), and a translating secondsleeve 230 (also referred to herein as a high speed inner sleeve or asecond sleeve). Low speed assembly 204 may generally comprise a screwmechanism comprising a rotating nut threadedly coupled to a translatingscrew. Low speed assembly 204 may comprise a rotating third sleeve 240(also referred to herein as a low speed outer sleeve or a third sleeve),and a translating screw 250 (also referred to herein as a low speedinner sleeve).

Although the present disclosure is described in accordance with variousembodiments on the basis of a screw mechanism having a rotating nut anda translating screw, it should be understood that the present disclosurecan be applied with a rotating screw and a translating nut, asillustrated in FIG. 15A and/or FIG. 16, for example.

Outer tube 210 may comprise a centerline axis 292. Outer tube 210 may behollow. First sleeve 220 may be disposed at least partially within outertube 210. First sleeve 220 may be hollow. Second sleeve 230 may bedisposed at least partially within first sleeve 220. Second sleeve 230may be hollow. Third sleeve 240 may be disposed at least partiallywithin second sleeve 230. Third sleeve 240 may be hollow. Translatingscrew 250 may be disposed at least partially within third sleeve 240.Translating screw 250 may be hollow. Lifting device 200 may furthercomprise a shaft 260. Shaft 260 may be disposed at least partiallywithin translating screw 250. In this regard, the inner diameter ofouter tube 210 may be greater than the outer diameter of first sleeve220. The inner diameter of first sleeve 220 may be greater than theouter diameter of second sleeve 230. The inner diameter of second sleeve230 may be greater than the outer diameter of third sleeve 240. Theinner diameter of third sleeve 240 may be greater than the outerdiameter of translating screw 250. The inner diameter of translatingscrew 250 may be greater than the outer diameter, or width, of shaft260. Outer tube 210, first sleeve 220, second sleeve 230, third sleeve240, translating screw 250, and shaft 260 are coaxially aligned and/orsubstantially coaxially aligned, but in various embodiments coaxialalignment is not present. One end of shaft 260 may bear a handle 270which may be used for rotating the shaft 260.

Lifting device 200 may further comprise a gear 265. Gear 265 may becoupled to, and rotate with, shaft 260. Gear 265 may be coaxiallyaligned with shaft 260. Shaft 260 may drive first sleeve 220 via gear265 in response to first sleeve 220 moving to a first position, asdescribed in further detail herein. Gear 265 may be splined to the shaft260 but gear 265 may also be fixedly coupled such as through welding,brazing, a press fit and/or an interference fit. Gear 265 may compriseany suitable gear, for example, a bevel gear or a crown gear.

Lifting device 200 may further comprise a spring 206. Spring 206 may bea coil spring, leaf spring, Belleville spring, or other suitable springfor exerting a bias against first sleeve 220. Spring 206 may beoperatively coupled to first sleeve 220, to assist movement of firstsleeve 220 between the first position and a second position, asdescribed herein with further detail. In this regard, first sleeve 220may be slidable in the outer tube 210 between the first position and thesecond position. First sleeve 220 may translate along centerline axis292 between the first position and the second position. The outer tube210 may comprise a retaining member 212. Retaining member 212 may becoupled to outer tube 210, e.g., via a threaded connection, fasteners,and/or a metal joining process, such as welding, brazing, etc. Retainingmember 212 may comprise a cap structure coupled to the upper end ofouter tube 210. Retaining member 212 may comprise a flange extendingradially inward from an inner diameter surface of outer tube 210. Shaft260 may extend through retaining member 212. Retaining member 212 mayretain spring 206 within outer tube 210. In this regard, spring 206 maybe compressed between retaining member 212 and first sleeve 220. Invarious embodiments, retaining member 212 comprises a mating surface 214configured to engage with a mating surface 224 of first sleeve 220 inresponse to first sleeve 220 moving to the second position (see FIG.4F). In this manner, first sleeve 220 may be restricted from rotatingwithin outer tube 210 in the second position. In various embodiments,and as shown, mating surface 224 and mating surface 214 are crenulatedand, as shown, having crenulations that are complementary to oneanother. The crenulations interact, in response to axial compression, totransfer torque to first sleeve 220.

In various embodiments, first sleeve 220 is threadedly coupled to secondsleeve 230. Thus, rotation of the first sleeve 220 causes the secondsleeve 230 to translate with respect to outer tube 210. Stateddifferently, high speed assembly 202 translates rotational motion offirst sleeve 220 to linear motion of second sleeve 230. In variousembodiments, third sleeve 240 is threadedly coupled to translating screw250. Thus, rotation of the third sleeve 240 causes the translating screw250 to translate with respect to outer tube 210. Stated differently, lowspeed assembly 204 translates rotational motion of third sleeve 240 tolinear motion of translating screw 250.

Various components of lifting device 200 may be made from a metal ormetal alloy, such as cast iron, steel, stainless steel, austeniticstainless steels, ferritic stainless steels, martensitic stainlesssteels, titanium, titanium alloys, aluminum, aluminum alloys, galvanizedsteel, or any other suitable metal or metal alloy. In this regard, outertube 210, first sleeve 220, second sleeve 230, third sleeve 240, andtranslating screw 250 may be made from a metal or metal alloy. It iscontemplated that various components of lifting device 200, such asouter tube 210, may be made from a fiber-reinforced composite material.

With combined reference to FIG. 2, FIG. 3A, and FIG. 3B, shaft 260 maybe operatively coupled to third sleeve 240 such that third sleeve 240rotates with shaft 260. In various embodiments, shaft 260 may compriseone or more splines 262 and third sleeve 240 may comprise a centeraperture 242 comprising a geometry that is complementary to shaft 260.In this regard, center aperture 242 may comprise one or more groovesconfigured to receive the one or more splines 262 of shaft 260 such thatshaft 260 interlocks with third sleeve 240 to impart rotational forces(i.e., torque) therebetween. Stated differently, third sleeve 240 andshaft 260 may be coupled via a splined connection. Third sleeve 240 maybe drivably coupled to shaft 260 via center aperture 242. Furthermore,although illustrated as a star shaped aperture, center aperture 242 maycomprise various geometries, such as triangular, square, or any othergeometry that interlocks shaft 260 with third sleeve 240. However, shaft260 may be operatively coupled to third sleeve 240 using various methodswithout departing from the scope and spirit of the present disclosure,such as via a fastener, for example.

In operation, rotation of shaft 260 in a first rotational direction,e.g., via handle 270, causes third sleeve 240 to rotate with respectouter tube 210 and translating screw 250, which in turn causestranslating screw 250 to extend from third sleeve 240 (see FIG. 4E andFIG. 4F). Conversely, rotation of shaft 260 in a second rotationaldirection (opposite the first rotational direction) causes third sleeve240 to rotate with respect outer tube 210 and translating screw 250,which in turn causes translating screw 250 to retract into third sleeve240 (see FIG. 4A and FIG. 4B).

Furthermore, with first sleeve 220 in a first position (see FIG. 4Athrough FIG. 4D) with respect to outer tube 210, first sleeve 220 may bedrivably coupled to shaft 260. Stated differently, rotation of shaft 260may drive rotation of first sleeve 220. In operation, and with firstsleeve 220 in a first position (see FIG. 4A through FIG. 4D) withrespect to outer tube 210 and/or gear 265, rotation of shaft 260 in afirst rotational direction, e.g., via handle 270, may cause first sleeve220 to rotate with respect outer tube 210 and second sleeve 230, whichin turn causes second sleeve 230 to extend from first sleeve 220.Conversely, rotation of shaft 260 in a second rotational direction(opposite the first rotational direction) may cause first sleeve 220 torotate with respect outer tube 210 and second sleeve 230, which in turncauses second sleeve 230 to retract into first sleeve 220. In the firstposition, spring 206 may bias first sleeve 220 to engage with gear 265.Thus, with the first sleeve 220 in the first position, both the secondsleeve 230 and the translating screw 250 are driven to translate withrespect to outer tube 210 in response to rotation of shaft 260.

However, in operation and with first sleeve 220 in a second position(see FIG. 4E and FIG. 4F) with respect to outer tube 210 and/or gear265, the first sleeve 220 is disengaged from gear 265 (i.e., rotation ofshaft 260 and gear 265 does not drive rotation of first sleeve 220 inthe disengaged position). In this regard, with first sleeve 220 in thesecond position, rotation of shaft 260 in the first rotational directionor the second rotational direction may cause only third sleeve 240 (andnot first sleeve 220) to rotate with respect to outer tube 210 andtranslating screw 250, thereby driving only the translating screw 250 totranslate. Stated differently, the high speed assembly 202 (i.e., thefirst sleeve 220 and second sleeve 230) may be disengaged from operationin response to the first sleeve 220 moving to the second position. Inthis manner, in response to rotation of shaft 260 in the firstdirection, both the high speed assembly 202 and the low speed assembly204 (i.e., the third sleeve 240 and translating screw 250) are driven toincrease the overall length of lifting device 200 but, after reactingforce from the ground through, for example, foot 275, rotation of shaft260 is only imparted to low speed assembly 204 and not high speedassembly 202. With momentary reference to FIG. 4E and FIG. 4F, as theoverall length of lifting device 200 is increased, the foot 275 of thelifting device 200 may contact a ground surface 402, thereby imparting aforce 404 from the ground surface 402 into the first sleeve 220 whichcauses the first sleeve 220 to move with respect to outer tube 210against the bias of spring 206 from the first position (i.e., engagedwith gear 265) to the second position (i.e., disengaged from gear 265)thereby decoupling first sleeve 220 from torsional forces imparted byshaft 260. In this regard, before the lifting device 200 has contacted aground surface, the overall length of the lifting device 200 is quicklyincreased to reduce the overall number of rotations of shaft 260 neededto cause lifting device 200 to reach the ground. In response tocontacting the ground, the high speed assembly 202 is decoupled from theshaft 260 to take advantage of the mechanical advantage of the low speedassembly 204. In this manner, time to operate is reduced relative toconventional designed and increased mechanical advantage is selectivelyactivated.

In various embodiments, second sleeve 230 comprises helically extendinggrooves or threads 232. In various embodiments, translating screw 250comprises helically extending grooves and/or threads 252. The threadpitch of threads 232 may be greater than the thread pitch of threads252. Stated differently, translating screw 250 may comprise more threadsper inch (TPI) than second sleeve 230. In various embodiments, thethread pitch of threads 232 is between 101% and 1000% as large as thethread pitch of threads 252, though various embodiments, the threadpitch of threads 232 is between 200% and 500% as large as the threadpitch of threads 252. In various embodiments, the thread pitch ofthreads 232 is more than twice as large as the thread pitch of threads252. In various embodiments, the thread pitch of threads 232 is morethan three times as large as the thread pitch of threads 252. In variousembodiments, the thread pitch of threads 232 is more than four times aslarge as the thread pitch of threads 252. It should be understood thatthe maximum thread pitch may be limited by the moment arm for torqueapplied to the shaft 260 and may be limited to reduce the torquerequirement for rotating shaft 260 below a desired threshold. In thismanner, the high speed assembly translates further and faster perrotation of shaft 260 than the low speed assembly, causing the liftingdevice 200 to reach a ground surface faster than if the high speedassembly were not present. Furthermore, in response to the liftingdevice 200 contacting a ground surface and the high speed assemblydisengaging from the shaft 260, the reduced thread pitch of the lowspeed assembly takes advantage of the reduced torque required forextending the lifting device 200.

The thread pitch of threads 232 may be between 0.1 millimeters (mm) and304.8 mm (between 0.0039 inches and 12 inches) in accordance withvarious embodiments, between 1 mm and 101.6 mm (between 0.039 inches and4 inches) in accordance with various embodiments, between 2 mm and 76.2mm (between 0.0787 inches and 3 inches) in accordance with variousembodiments, and/or between 4 mm and 50.8 mm (between 0.157 inches and 2inches) in accordance with various embodiments.

The thread pitch of threads 252 may be between 0.1 millimeters (mm) and279.4 mm (between 0.0039 inches and 11 inches) in accordance withvarious embodiments, between 1 mm and 25.4 mm (between 0.039 inches and1 inch) in accordance with various embodiments, between 1 mm and 6.35 mm(between 0.039 inches and 0.25 inches) in accordance with variousembodiments, and/or between 2 mm and 3.175 mm (between 0.0787 inches and0.125 inches) in accordance with various embodiments.

With reference to FIG. 2 and FIG. 4B, second sleeve 230 may be keyed toouter tube 210 to prevent rotation of second sleeve 230 with respect toouter tube 210. For example, second sleeve 230 may comprise one or moreaxially extending grooves 234 (see FIG. 2) disposed in the outerdiameter surface thereof and outer tube 210 may comprise correspondingprotrusion(s) 216 extending radially inwards from an inner diametersurface thereof that extends into groove(s) 234.

With reference to FIG. 5A and FIG. 5B, the lifting device of FIG. 4Awith the outer tube, spring, and retaining member omitted isillustrated, in accordance with various embodiments. In variousembodiments, translating screw 250 may be keyed to second sleeve 230 toprevent rotation of translating screw 250 with respect to second sleeve230 and outer tube 210. For example, translating screw 250 may compriseone or more axially extending grooves 254 (see FIG. 2) disposed in theouter diameter surface thereof and second sleeve 230 may comprisecorresponding protrusion(s) 236 extending radially inwards from an innerdiameter surface thereof that extends into groove(s) 254.

With reference to FIG. 6A and FIG. 6B, the lifting device of FIG. 5Awith the first sleeve 220 further omitted is illustrated, in accordancewith various embodiments. Gear 265 may be slid onto shaft 260 just abovesecond sleeve 230, in accordance with various embodiments. Second sleeve230 may comprise a flange 238 at an upper end thereof extending radiallyinward to form an end wall through which shaft 260 extends. Furthermore,an upper end of third sleeve 240 may abut flange 238.

With reference to FIG. 7A and FIG. 7B, high speed first sleeve 220 isillustrated, in accordance with various embodiments. First sleeve 220may comprise a radially inward extending flange 222 forming an end wallat the upper end of first sleeve 220. Shaft 260 (see FIG. 5B) may extendthrough flange 222. First sleeve 220 may comprise a plurality of teeth226. Plurality of teeth 226 may be disposed on flange 222. Plurality ofteeth 226 may be in meshing relationship with gear 265 (see FIG. 4B) inresponse to first sleeve 220 moving to the first position whereby shaft260 may be drivably coupled to shaft 260. Plurality of teeth 226 mayfurther comprise crenulations to complement gear 265, in variousembodiments. First sleeve 220 may comprise helically extending ridges228 (also referred to herein as threads). Threads 228 may be disposed onan inner diameter surface of first sleeve 220. Threads 228 may engagewith complementary threads 232 (See FIG. 2) disposed on second sleeve230. Threads 228 and threads 232 may assist in translating rotationalmotion of first sleeve 220 into linear motion of second sleeve 230.

With reference to FIG. 8A and FIG. 8B, low speed assembly 204 isillustrated, in accordance with various embodiments. Third sleeve 240may comprise helically extending ridges 244 (also referred to herein asthreads). Threads 244 may be disposed on an inner diameter surface ofthird sleeve 240. Threads 244 may engage with complementary threads 252disposed on translating screw 250. Threads 244 and threads 252 mayassist in translating rotational motion of third sleeve 240 into linearmotion of translating screw 250.

With reference to FIG. 9A, FIG. 9B, and FIG. 9C, low speed outer sleeve240 is illustrated, in accordance with various embodiments. Third sleeve240 may comprise a radially inward extending flange 246 forming an endwall at the upper end of third sleeve 240. Center aperture 242 may bedisposed in flange 246. Shaft 260 (see FIG. 5B) may extend throughflange 246.

With respect to FIG. 10A and FIG. 10B, elements with like elementnumbering, as depicted in FIG. 2, are intended to be the same and willnot necessarily be repeated for the sake of clarity.

With reference to FIG. 10A and FIG. 10B, a lifting device 300 with anattachment feature 318 coupled to the outer tube 310 is illustrated, inaccordance with various embodiments. Lifting device 300 may be similarto lifting device 200 of FIG. 2. Lifting device 300 may be attached to atrailer (e.g., trailer 120 of FIG. 1) via attachment feature 318. Inthis manner, outer tube 310 may be substantially fixed to the trailerduring operation, thereby preventing rotation of outer tube 310 andsupporting the trailer. Attachment feature 318 may comprise a tube 319coupled to the outer diameter surface of outer tube 310 for attachingthe lifting device 300 to a trailer in a known manner. Tube 319 may beoriented substantially perpendicular with respect to outer tube 310.Tube 319 may provide a pivot connection between lifting device 300 and atrailer or vehicle to allow lifting device 300 to be rotated between astowed position and a deployed position.

With reference to FIG. 11A and FIG. 11B, an outer tube 410 comprising anattachment feature 418 is illustrated, in accordance with variousembodiments. Outer tube 410 may be similar to outer tube 210 of FIG. 2.Attachment feature 418 may comprise a collar 419 coupled to ansurrounding the outer diameter surface of outer tube 410. Collar 419 maycomprise a plurality of apertures for coupling collar 419 to a traileror vehicle via a plurality of fasteners, such as bolts, in a knownmanner. Collar 419 may be coupled to outer tube 410 via a metal joiningprocess, such as welding for example. In various embodiments, outer tube410 may be welded directly to a trailer or vehicle, without the use of adedicated attachment feature.

With respect to FIG. 12, elements with like element numbering, asdepicted in FIG. 2, are intended to be the same and will not necessarilybe repeated for the sake of clarity.

With reference to FIG. 12, a trailer landing gear assembly 500 isillustrated, in accordance with various embodiments. Some trailers mayuse landing gear, generally comprising a pair of retractable legs, atthe front end of the trailer to support said front end when the traileris to be detached from a truck or tractor. Landing gear assembly 500 hasa driven crank 580 which passes through the upper ends of a pair oftelescoping, vertical legs or lifting devices 501, 502. With additionalreference to FIG. 13A and FIG. 13B, each lifting device 501, 502 may besimilar to lifting device 200 of FIG. 2, except that the upper end ofthe shaft 560 of the lifting device bears a gear 564 (also referred toherein as a second gear) in meshing relation with a gear 582 (alsoreferred to herein as a third gear) disposed on the crank 580. In thismanner, rotation of crank 580 drives rotation of shaft 560. Crank 580 isdisposed substantially perpendicular with respect to shaft 560. Gear 564may be a bevel gear. Gear 582 may be a bevel gear. However, other typesof gears known for connecting perpendicularly disposed rods may be usedwithout departing from the spirit and scope of the present disclosure.

With reference to FIG. 14, a cross-section view of lifting device 501 isillustrated, in accordance with various embodiments. Outer tube 510 maycomprise one or more aligned apertures 518 disposed in the upper end ofouter tube 510 through which crank 580 extends.

With reference to FIG. 15A and FIG. 15B, a lifting device 600 isillustrated, in accordance with various embodiments. Lifting device 600may be similar to lifting device 200 (e.g., see FIG. 2 and FIG. 4B),except that, instead of the low speed assembly having a rotating sleeveand a translating screw, the low speed assembly of lifting device 600has a rotating screw 650 and a translating sleeve 640.

Lifting device 600 may comprise a shaft 660 operatively coupled torotating screw 650 such that rotating screw 650 rotates with shaft 660.In various embodiments, shaft 660 may comprise one or more splines 662and rotating screw 650 may comprise a center aperture 656 comprising ageometry that is complementary to shaft 660. In this regard, centeraperture 656 may comprise one or more grooves configured to receive theone or more splines 662 of shaft 660 such that shaft 660 interlocks withrotating screw 650 to impart rotational forces (i.e., torque)therebetween. Stated differently, aperture 656 and shaft 660 may becoupled via a splined connection. Rotating screw 650 may be drivablycoupled to shaft 660 via center aperture 656. Center aperture 656 maycomprise various geometries, such as triangular, square, or any othergeometry that interlocks shaft 660 with rotating screw 650. Shaft 660may be operatively coupled to rotating screw 650 using various methodswithout departing from the scope and spirit of the present disclosure,such as via a fastener, for example.

In operation, rotation of shaft 660 in a first rotational direction,e.g., via handle 670, causes rotating screw 650 to rotate with respectto outer tube 610 and translating sleeve 640, which in turn causestranslating sleeve 640 to extend from rotating screw 650. Conversely,rotation of shaft 660 in a second rotational direction (opposite thefirst rotational direction) causes rotating screw 650 to rotate withrespect to outer tube 610 and translating sleeve 640, which in turncauses translating sleeve 640 to retract into outer tube 610.

With reference to FIG. 16, an exploded view of a lifting device 700 isillustrated, in accordance with various embodiments. Lifting device 700may be a linear jack. Lifting device 700 may operate similar to liftingdevice 200, except that instead of comprising a low speed assemblynested within a high speed assembly, lifting device 700 of FIG. 16comprises a high speed assembly 702 nested within a low speed assembly704.

Lifting device 700 may generally comprise an outer tube 710, a highspeed assembly 702, and a low speed assembly 704. High speed assembly702 may generally comprise a screw mechanism comprising a rotating screwthreadedly coupled to a translating nut. In various embodiments, highspeed assembly 702 comprises a translating sleeve 720 (also referred toherein as a high speed outer sleeve or a first sleeve), and a rotatingscrew 730 (also referred to herein as a high speed inner sleeve, or arotating inner sleeve). Low speed assembly 704 may generally comprise ascrew mechanism comprising a rotating screw threadedly coupled to atranslating nut. Low speed assembly 704 may comprise a translatingsleeve 740 (also referred to herein as a low speed outer sleeve), and arotating sleeve 750 (also referred to herein as a low speed innersleeve).

Outer tube 710 may comprise a centerline axis 792. Outer tube 710 may behollow. Sleeve 740 may be disposed at least partially within outer tube710. Sleeve 740 may be hollow. Sleeve 750 may be disposed at leastpartially within sleeve 740. Sleeve 750 may be hollow. Sleeve 720 may bedisposed at least partially within sleeve 750. Sleeve 720 may be hollow.Rotating screw 730 may be disposed at least partially within sleeve 720.Rotating screw 730 may be hollow. Lifting device 700 may furthercomprise a shaft 760 (also referred to herein as a first shaft). Shaft760 may be hollow. Lifting device 700 may further comprise a shaft 766(also referred to herein as a second shaft). Shaft 760 may be disposedat least partially within rotating screw 730. Shaft 766 may be disposedat least partially within shaft 760. Shaft 766 may be disposed at leastpartially within rotating screw 730. In this regard, the inner diameterof outer tube 710 may be greater than the outer diameter of sleeve 740.The inner diameter of sleeve 740 may be greater than the outer diameterof sleeve 750. The inner diameter of sleeve 750 may be greater than theouter diameter of sleeve 720. The inner diameter of sleeve 720 may begreater than the outer diameter of rotating screw 730. Outer tube 710,sleeve 740, sleeve 750, sleeve 720, rotating screw 730, shaft 760, andshaft 766 may be coaxially aligned.

Lifting device 700 may further comprise a gear 765. Gear 765 may becoupled to, and rotate with, shaft 760. Gear 765 may be coaxiallyaligned with shaft 760. Shaft 760 may drive rotating screw 730 via gear765 in response to rotating screw 730 moving to a first position withrespect to shaft 760, as described in further detail herein.

Lifting device 700 may further comprise a spring 706. Spring 706 may beoperatively coupled to rotating screw 730, to assist movement ofrotating screw 730 between the first position and a second position, asdescribed herein in further detail. In this regard, rotating screw 730may be slidable in the outer tube 210 between the first position and thesecond position. Rotating screw 730 may comprise a mating surface 734.Mating surface 734 may be in meshing relationship with gear 765 inresponse to rotating screw 730 moving to the first position, asillustrated in FIG. 17B. Mating surface 734 may comprise a plurality ofteeth. Rotating screw 730 may comprise a flange 736 extending radiallyinward from an inner diameter surface of rotating screw 730. Matingsurface 734 may be disposed on flange 736. Shaft 760 may extend throughflange 736 of rotating screw 730. Rotating screw 730 may comprise aflange 737 extending radially inward from the inner diameter surface ofrotating screw 730. Shaft 766 may extend through flange 737 of rotatingscrew 730. Spring 706 may be disposed between flange 736 and flange 737.Spring 706 may be compressed between flange 737 and gear 765. Rotatingscrew 730 may comprise a flange 738 extending radially inward from theinner diameter surface of rotating screw 730. Flange 737 may be disposedaxially between and spaced apart from flange 736 and flange 738. Shaft766 may be spaced apart from flange 738 of rotating screw 730 inresponse to rotating screw 730 moving to the first position, asillustrated in FIG. 17B. Shaft 766 may engage (i.e., may enter intocontact with) flange 738 of rotating screw 730 in response to rotatingscrew 730 moving to the second position, as illustrated in FIG. 17D. Inresponse to rotating screw 730 moving to the second position, shaft 766may be in meshing relation with flange 738 to prevent rotation ofrotating screw 730 with respect to shaft 766 and/or shaft 760. In thismanner, rotating screw 730 may be restricted from rotating within outertube 210 in the second position.

In various embodiments, rotating screw 730 is threadedly coupled tosleeve 720. Thus, rotation of the rotating screw 730 causes the sleeve720 to translate with respect to outer tube 210. Stated differently,high speed assembly 702 translates rotational motion of rotating screw730 to linear motion of sleeve 720. In various embodiments, sleeve 750is threadedly coupled to sleeve 740. Thus, rotation of the sleeve 750causes the sleeve 740 to translate with respect to outer tube 710.Stated differently, low speed assembly 204 translates rotational motionof sleeve 750 to linear motion of sleeve 740.

Sleeve 720 may comprise a flange 722 extending radially outward from anouter diameter surface of sleeve 720 at the upper end thereof. Sleeve750 may comprise a flange 756 extending radially outward from an outerdiameter surface of sleeve 750 at the upper end thereof. Sleeve 720 mayrotate with respect to sleeve 750. A bearing 708 may be disposed betweenflange 722 and flange 756 to reduce friction between sleeve 720 andsleeve 750. Bearing 708 may comprise a thrust needle roller bearing orthe like, in accordance with various embodiments.

In various embodiments, the upper end of the shaft 760 may bear a gear764 in meshing relation with a gear 782 disposed on a crank 780. In thismanner, rotation of crank 780 drives rotation of shaft 760. Crank 780may be disposed substantially perpendicular with respect to shaft 760.Gear 764 may be a bevel gear. Gear 782 may be a bevel gear. However,other types of gears known for connecting perpendicularly disposed rodsmay be used without departing from the spirit and scope of the presentdisclosure. One end of crank 780 may bear a handle 770 which may be usedfor rotating the crank 780.

A radially inward extending flange 712 may be disposed at an upper endof outer tube 710. Shaft 760 may extend through flange 712. Shaft 760may be at least partially supported by flange 712. Shaft 760 maycomprise a shoulder which abuts flange 712. In this manner, flange 712may prevent shaft 760 from translating within outer tube 710. A cap 718may be coupled to the upper end of outer tube 710. Cap 718 may enclosegear 782 and gear 764. Cap 718 may comprise an aperture 719 throughwhich crank 780 extends. Crank 780 may be supported by cap 718.

With combined reference to FIG. 16 and FIG. 17B, shaft 760 may beoperatively coupled to sleeve 750 such that sleeve 750 rotates withshaft 760. In various embodiments, shaft 760 may comprise one or moresplines 762 and sleeve 750 may comprise a center aperture 759 comprisinga geometry that is complementary to shaft 760. In this regard, centeraperture 759 may comprise one or more grooves configured to receive theone or more splines 762 of shaft 760 such that shaft 760 interlocks withsleeve 750 to impart rotational forces (i.e., torque) therebetween.Stated differently, aperture 759 and shaft 760 may be coupled via asplined connection. Sleeve 750 may be drivably coupled to shaft 760 viacenter aperture 759. Furthermore, although illustrated as a star shapedaperture, center aperture 759 may comprise various geometries, such astriangular, square, or any other geometry that interlocks shaft 760 withsleeve 750. However, shaft 760 may be operatively coupled to sleeve 750using various methods without departing from the scope and spirit of thepresent disclosure, such as via a fastener, for example.

Sleeve 750 may comprise a cap 758 coupled to flange 756. Flange 722 maybe installed in a gap formed between cap 758 and flange 756. Bearing 708may similarly be installed in the gap formed between cap 758 and flange756. Center aperture 759 may be disposed in cap 758. Cap 758 may becoupled to sleeve 750 via any suitable connection, including welding,fasteners, a threaded connection, etc.

In operation, rotation of shaft 760 in a first rotational direction,e.g., via handle 770, causes sleeve 750 to rotate with respect outertube 710 and translating sleeve 740, which in turn causes translatingsleeve 740 to extend from outer tube 710 (see FIG. 17C and FIG. 17D).Conversely, rotation of shaft 760 in a second rotational direction(opposite the first rotational direction) causes sleeve 750 to rotatewith respect outer tube 710 and translating sleeve 740, which in turncauses translating sleeve 740 to retract into outer tube 710 (see FIG.17A and FIG. 17B).

Furthermore, with rotating screw 730 in a first position (see FIG. 17Aand FIG. 17B) with respect to outer tube 710, rotating screw 730 may bedrivably coupled to shaft 760. Stated differently, rotation of shaft 760may drive rotation of rotating screw 730. In operation, and withrotating screw 730 in a first position (see FIG. 4A through FIG. 4D)with respect to outer tube 710 and/or gear 765, rotation of shaft 760 ina first rotational direction, e.g., via handle 770, may cause rotatingscrew 730 to rotate with respect outer tube 710 and sleeve 720, which inturn causes sleeve 720 to translate with respect to rotating screw 730and extend from outer tube 710. Conversely, rotation of shaft 760 in asecond rotational direction (opposite the first rotational direction)may cause rotating screw 730 to rotate with respect outer tube 710 andsleeve 720, which in turn causes sleeve 720 to retract into outer tube710. In the first position, spring 706 may bias rotating screw 730 toengage with gear 765. Thus, with the rotating screw 730 in the firstposition, both the sleeve 720 and the sleeve 740 are driven to translatewith respect to outer tube 710 in response to rotation of shaft 760.

However, in operation and with rotating screw 730 in a second position(see FIG. 17C and FIG. 17D) with respect to outer tube 710 and/or gear765, the rotating screw 730 is disengaged from gear 765 (i.e., rotationof shaft 760 and gear 765 does not drive rotation of rotating screw 730in the disengaged position). In this regard, with rotating screw 730 inthe second position, rotation of shaft 760 in the first rotationaldirection or the second rotational direction may cause only sleeve 750(and not rotating screw 730) to rotate with respect to outer tube 710and sleeve 720, thereby driving only the sleeve 740 to translate. Stateddifferently, the high speed assembly 702 (i.e., the rotating screw 730and sleeve 720) may be disengaged from operation in response to therotating screw 730 moving to the second position. In this manner, inresponse to rotation of shaft 760 in the first direction, both the highspeed assembly 702 and the low speed assembly 704 are driven to increasethe overall length of lifting device 700. With momentary reference toFIG. 17C and FIG. 17D, as the overall length of lifting device 700 isincreased, the foot 775 of the lifting device 700 may contact a groundsurface 790, thereby imparting a force 794 from the ground surface 790into the rotating screw 730 which causes the rotating screw 730 to movewith respect to outer tube 710 against the bias of spring 706 from thefirst position (i.e., engaged with gear 765) to the second position(i.e., disengaged from gear 765) thereby decoupling rotating screw 730from torsional forces imparted by shaft 760. In this regard, before thelifting device 700 has contacted a ground surface, the overall length ofthe lifting device 700 is quickly increased to reduce the overall numberof rotations of shaft 760 required to cause lifting device 700 to reachthe ground. In response to contacting the ground, the high speedassembly 702 is decoupled from the shaft 760 to take advantage of themechanical advantage of the low speed assembly 704.

In various embodiments, rotating screw 730 comprises helically extendinggrooves or threads 732. In various embodiments, sleeve 750 compriseshelically extending grooves and/or threads 752. The thread pitch ofthreads 732 may be greater than the thread pitch of threads 752. Stateddifferently, sleeve 750 may comprise more threads per inch (TPI) thanrotating screw 730. In various embodiments, the thread pitch of threads732 is more than twice as large as the thread pitch of threads 752. Invarious embodiments, the thread pitch of threads 732 is more than threetimes as large as the thread pitch of threads 752. In variousembodiments, the thread pitch of threads 732 is more than four times aslarge as the thread pitch of threads 752. It should be understood thatthe maximum thread pitch may be limited by the moment arm for torqueapplied to the shaft 760 and may be limited below a desired threshold toreduce the torque requirement for rotating shaft 760. In this manner,the high speed assembly 702 translates further and faster per rotationof shaft 760 than the low speed assembly 704, causing the lifting device700 to reach a ground surface faster than if the high speed assemblywere not present. Furthermore, in response to the lifting device 700contacting a ground surface and the high speed assembly 702 disengagingfrom the shaft 760, the reduced thread pitch of the low speed assembly704 is taken advantage of to reduce the torque required for extendingthe lifting device 700.

With reference to FIG. 16 and FIG. 17D, sleeve 740 may be keyed to outertube 710 to prevent rotation of sleeve 740 with respect to outer tube710. For example, sleeve 740 may comprise one or more axially extendinggrooves 748 (see FIG. 16) disposed in the outer diameter surface thereofand outer tube 710 may comprise corresponding protrusion(s) 716 (seeFIG. 17D) extending radially inwards from an inner diameter surfacethereof that extend(s) into groove(s) 748.

With reference to FIG. 18, a flow chart of a method 800 of manufacturinga lifting device, such as a linear jack, is illustrated, in accordancewith various embodiments. Method 800 includes disposing a second sleeveat least partially within a first sleeve (step 810). Method 800 includesdisposing a translating screw at least partially within a third sleeve(step 820). Method 800 includes disposing the third sleeve at leastpartially within the second sleeve (step 830).

With combined reference to FIG. 2 and FIG. 18, step 810 may includethreading second sleeve 230 into first sleeve 220. Step 820 may includethreading screw 250 into third sleeve 240. Step 830 may include movingthird sleeve 240 at least partially into second sleeve 230. First sleeve220 may be moved into outer tube 210 via the open upper end of outertube 210 prior to retaining member 212 being coupled to the upper end ofouter tube 210.

With respect to FIG. 19A and FIG. 19B, elements with like elementnumbering, as depicted in FIG. 4A and FIG. 4B, are intended to be thesame and will not necessarily be repeated for the sake of clarity.

With reference to FIG. 19A and FIG. 19B, a lifting device 201 isillustrated, in accordance with various embodiments. Lifting device 201may be similar to lifting device 200 of FIG. 2, except that the threadpitch of second sleeve 230 and first sleeve 220 is equal to the threadpitch of third sleeve 240 and screw 250. In this regard, first sleeve220 may comprise helically extending threads 229. Threads 229 may bedisposed on an inner diameter surface of first sleeve 220. Second sleeve230 may comprise helically extending threads 233. Threads 233 may bedisposed on an outer diameter surface of second sleeve 230. The threadpitch of threads 233 and threads 229 may be equal to the thread pitch ofthreads 252 of screw 250 and threads 244 of third sleeve 240 (see FIG.8A and FIG. 8B).

With reference to FIG. 20, an exploded view of a lifting device 900 isillustrated, in accordance with various embodiments. Lifting device 900may be a linear jack. Lifting device 900 may generally comprise an outertube 910, a high speed assembly 902, and a low speed assembly 904. Highspeed assembly 902 may generally comprise a screw mechanism comprising arotating nut threadedly coupled to a translating screw, in the manner ofa leadscrew or jack screw. In various embodiments, high speed assembly902 comprises a rotating sleeve 940, and a translating screw 950. Lowspeed assembly 904 may generally comprise a screw mechanism comprising arotating nut threadedly coupled to a translating screw. Low speedassembly 904 may comprise a rotating sleeve 920, and a translatingsleeve 930.

Although the present disclosure is described in accordance with variousembodiments on the basis of a screw mechanism having a rotating nut anda translating screw, it should be understood that the present disclosurecan be applied with a rotating screw and a translating nut, asillustrated in FIG. 15A and/or FIG. 16, for example.

Outer tube 910 may comprise a centerline axis 992. Outer tube 910 may behollow. Sleeve 920 may be disposed at least partially within outer tube910. In various embodiments, sleeve 920 is placed into the open upperend of outer tube 910 prior to retaining member 912 being coupled toouter tube 910. Sleeve 920 may be hollow. Sleeve 930 may be disposed atleast partially within sleeve 920. Sleeve 930 may be hollow. Sleeve 940may be disposed at least partially within sleeve 930. Sleeve 940 may behollow. Translating screw 950 may be disposed at least partially withinsleeve 940. Translating screw 950 may be hollow. Lifting device 900 mayfurther comprise a shaft 960 (also referred to herein as an inputshaft). Shaft 960 may be disposed at least partially within outer tube910. Lifting device 900 may further comprise a shaft 966 (also referredto herein as an output shaft). Shaft 960 may be disposed at leastpartially within screw 950. In this regard, the inner diameter of outertube 910 may be greater than the outer diameter of sleeve 920. The innerdiameter of sleeve 920 may be greater than the outer diameter of sleeve930. The inner diameter of sleeve 930 may be greater than the outerdiameter of sleeve 940. The inner diameter of sleeve 940 may be greaterthan the outer diameter of translating screw 950. The inner diameter oftranslating screw 950 may be greater than the outer diameter, or width,of shaft 966. Outer tube 910, sleeve 920, sleeve 930, sleeve 940,translating screw 950, shaft 960, and shaft 966 may be coaxially alignedand/or substantially coaxially aligned, but in various embodimentscoaxial alignment is not present. One end of shaft 960 may bear a handle970 which may be used for rotating the shaft 960.

Lifting device 900 may further comprise a planetary gear system 980. Theplanetary gear system 980 in various embodiments as shown includes aring gear 981, one or more planet gears 982, and a sun gear 983. Thesystem 980 may include one, two, three, four, five, six, seven, eight,or more planet gears 982. Each of the gears 981, 982, 983 includes aplurality of teeth. For example, the ring gear 981 includes teeth 132,each planet gear 982 includes teeth 134, and sun gear 983 includes teeth136. The teeth 132, 134, and 136 are sized and shaped to mesh togethersuch that the various gears 981, 982, 983 engage each other. Forexample, the ring gear 981 and the sun gear 983 may each engage theplanet gears 982 a, 982 b, 982 c.

The planetary gear system 980 may include a carrier 984 comprising afirst plate 985 a and a second plate 985 b. Planet gears 982 a, 982 b,982 c may be rotatably coupled to carrier 984—e.g., supported betweenfirst plate 985 a and second plate 985 b. Carrier 984 may furthercomprise a capped flange 986. Capped flange may comprise a splinedaperture 122 configured to receive shaft 960. Splined aperture 122 mayinterlock with splines 962 disposed on shaft 960. In this manner,torsional forces may be transmitted from shaft 960 into carrier 984 viacapped flange 986.

In various embodiments, the ring gear 981 may be stationary. Forexample, ring gear 981 may be fixed to the inner diameter surface ofouter tube 910, such as via a splined connection, a threaded connection,a friction fit, a snap fit, a weld, or the like. In these embodiments,the input shaft may be coupled to the carrier 984, and input loads(e.g., torque) on the input shaft 960 may be transmitted through thecarrier 984 to the planet gears 982 a, 982 b, 982 c. Thus, the carrier984 may drive the system 980.

First plate 985 a and second plate 985 b may comprise a first pluralityof holes aligned to receive a plurality of bolts, such as bolt 142 a,bolt 142 b, and bolt 142 c, for example. Capped flange 986 may similarlycomprise a plurality of holes aligned to receive the plurality of bolts142 a, 142 b, 142 c. In various embodiments, bolt 142 a, bolt 142 b, andbolt 142 c hold capped flange 986, first plate 985 a, and a second plate985 b together. First plate 985 a and second plate 985 b may comprise asecond plurality of holes aligned to receive shafts associated withplanet gears 982 a, 982 b, 982 c. In this manner, bolts 142 a, 142 b,142 c may each extend between adjacent planet gears 982 a, 982 b, 982 c.

Sleeve 920 may be drivably coupled to shaft 960. In various embodiments,bolts 142 may extend into holes 144 disposed in flange 924 of sleeve920. Input loads (e.g., torque) may be transmitted from shaft 960,through carrier 984 and bolts 142, into sleeve 920. In this manner,sleeve 920 may rotate at a 1:1 ratio with shaft 960.

The outer tube 910 may comprise a retaining member 912. Retaining member912 may be coupled to outer tube 910, e.g., via a threaded connection,snap fit, friction fit, fasteners, and/or a metal joining process, suchas welding, brazing, etc. Retaining member 912 may comprise a capstructure coupled to the upper end of outer tube 910. Retaining member912 may comprise a flange extending radially inward from outer tube 910.Shaft 960 may extend through retaining member 912. Lifting device 900may further comprise a bearing 908 supporting, at least in part, shaft960. Bearing 908 may be disposed between retaining member 912 and cappedflange 986. Shaft 960 may extend through bearing 908.

Lifting device 900 may further comprise a spring 906. Spring 906 may bea coil spring, leaf spring, Belleville spring, or other suitable springfor exerting a bias against sun gear 983. Spring 906 may be operativelycoupled to sleeve 920 and sun gear 983, via shaft 966, to assistmovement of sleeve 920 and sun gear 983 between first and secondpositions, as described herein with further detail. In this regard,sleeve 920 may be slidable in the outer tube 910 between the firstposition and the second position. Sleeve 920 may translate alongcenterline axis 992 between the first position and the second position.Spring 906 may be compressed between capped flange 986 and shaft 960, inaccordance with various embodiments. Spring 906 may be compressedbetween capped flange 986 and sun gear 983, in accordance with variousembodiments. Spring 906 may bias shaft 960, shaft 966, sun gear 983, andsleeve 920 to translate together with respect to outer tube 910 betweenthe first position (see FIG. 21B) and the second position (see FIG.21D). Sleeve 920 may translate with respect to, and about, bolts 142between the first position and the second position.

With combined reference to FIG. 20, FIG. 21A, and FIG. 21B, rotation ofshaft 960 may drive rotation of carrier 984 (e.g., via splined aperture122), wherein, in response, the carrier 984 drives rotation of bolts 142a, 142 b, 142 c, wherein, in response, the bolts 142 a, 142 b, 142 cdrive rotation of sleeve 920. In various embodiments, sleeve 920 isthreadedly coupled to sleeve 930. Thus, rotation of the sleeve 920causes the sleeve 930 to translate with respect to outer tube 910.Stated differently, low speed assembly 904 translates rotational motionof sleeve 920 to linear motion of sleeve 930. Low speed assembly 904 maybe driven by shaft 960 regardless of the position of sleeve 920 and/orsun gear 983, in accordance with various embodiments.

Furthermore, with sleeve 920 in the first position (see FIG. 21B) withrespect to outer tube 910, spring 906 biases sun gear 983 in meshingrelation with planet gears 982. In this regard, sleeve 940 may bedrivably coupled to shaft 960 via planetary gear system 980. Rotation ofshaft 960 may drive rotation of carrier 984 (e.g., via splined aperture122), wherein, in response, the carrier 984 drives rotation of planetgears 982 a, 982 b, 982 c, wherein, in response, the planet gears 982 a,982 b, 982 c drive rotation of shaft 966, wherein, in response, shaft966 drives rotation of sleeve 940. In various embodiments, sleeve 940 isthreadedly coupled to translating screw 950. Thus, rotation of thesleeve 940 causes the translating screw 950 to translate with respect toouter tube 910. Stated differently, high speed assembly 902 translatesrotational motion of sleeve 940 to linear motion of translating screw950.

In various embodiments, rotation of shaft 960 may drive rotation ofshaft 966 at a 1:n ratio, wherein n is greater than 1. In variousembodiments, n is equal to the number of rotations of shaft 966 perrotation of shaft 960. Planetary gear system 980 may be geared to anysuitable ratio which causes shaft 966 to rotate faster than shaft 960,thus causing sleeve 940 to rotate faster than sleeve 920.

In various embodiments, with sleeve 920 in the first position (see FIG.21B) with respect to outer tube 910 and sun gear 983 in meshing relationwith planet gears 982, rotation of shaft 960 in a first rotationaldirection, e.g., via handle 970, may cause sleeve 940 to rotate withrespect outer tube 910 and translating screw 950, which in turn causestranslating screw 950 to extend from sleeve 940. Conversely, rotation ofshaft 960 in a second rotational direction (opposite the firstrotational direction) may cause sleeve 940 to rotate with respect outertube 910 and translating screw 950, which in turn causes translatingscrew 950 to retract into sleeve 940. In the first position, spring 906may bias sun gear 983 to engage with planet gears 982. Thus, with thesun gear 983 in the first position, both the sleeve 930 and thetranslating screw 950 are driven to translate with respect to outer tube910 in response to rotation of shaft 960.

However, in operation and with sleeve 920 and sun gear 983 in secondpositions (see FIG. 21D) with respect to outer tube 910 and/or planetgears 982, the sun gear 983 (and thus the output shaft 966) isdisengaged from planet gears 982 (i.e., rotation of shaft 960 does notdrive rotation of output shaft 966 and sleeve 940 in the disengagedposition). In this regard, with sun gear 983 in the second position,rotation of shaft 960 in the first rotational direction or the secondrotational direction may cause only sleeve 920 (and not sleeve 940) torotate with respect to outer tube 910, thereby driving only the sleeve930 to translate. Stated differently, the high speed assembly 902 (i.e.,the sleeve 940 and translating screw 950) may be disengaged fromoperation in response to the sleeve 920 and/or sun gear 983 moving tothe second position. In this manner, in response to rotation of shaft960 in the first direction, both the high speed assembly 902 and the lowspeed assembly 904 (i.e., the sleeve 920 and sleeve 930) are driven toincrease the overall length of lifting device 900 but, after reactingforce from the ground through, for example, foot 975, rotation of shaft960 is only imparted to low speed assembly 904 and not high speedassembly 902. With momentary reference to FIG. 21C and FIG. 21D, as theoverall length of lifting device 900 is increased, the foot 975 of thelifting device 900 may contact a ground surface 402, thereby imparting aforce 404 from the ground surface 402 into the sleeve 920 which causesthe sleeve 920 to move with respect to outer tube 910 against the biasof spring 906 from the first position. Said force may be transmittedthrough sleeve 920 into shaft 966, thereby pushing shaft 966 upwardsagainst the bias of spring 906 and removing sun gear 983 from meshingrelation with planet gears 982. In this manner, sun gear 983 may movefrom the first position (i.e., engaged with planet gears 982) to thesecond position (i.e., disengaged from planet gears 982) therebydecoupling sleeve 940 from torsional forces imparted by shaft 960. Inthis regard, before the lifting device 900 has contacted a groundsurface, the overall length of the lifting device 900 is quicklyincreased to reduce the overall number of rotations of shaft 960 neededto cause lifting device 900 to reach the ground. In response tocontacting the ground, the high speed assembly 902 is decoupled from theshaft 960 to take advantage of the mechanical advantage of the low speedassembly 904. In this manner, time to operate is reduced relative toconventional designed and increased mechanical advantage is selectivelyactivated.

In various embodiments, sleeve 930 comprises threads 932. In variousembodiments, translating screw 950 comprises threads 952. The threadpitch of threads 932 may be equal to, less than, or greater than thethread pitch of threads 952. In various embodiments, the thread pitch ofthreads 932 is equal to the thread pitch of threads 952. In response toshaft 966 rotating faster than shaft 960, translating screw 950 maytranslate faster in linear distance than sleeve 930, even though threads952 and threads 932 may comprise the same thread pitch.

With reference to FIG. 20 and FIG. 4B, sleeve 930 may be keyed to outertube 910 to prevent rotation of sleeve 930 with respect to outer tube910. For example, sleeve 930 may comprise one or more axially extendinggrooves 934 (see FIG. 20) disposed in the outer diameter surface thereofand outer tube 910 may comprise corresponding protrusion(s) 916extending radially inwards from an inner diameter surface thereof thatextends into groove(s) 934.

In various embodiments, translating screw 950 may be keyed to sleeve 930to prevent rotation of translating screw 950 with respect to sleeve 930and outer tube 910. For example, translating screw 950 may comprise oneor more axially extending grooves 954 (see FIG. 20) disposed in theouter diameter surface thereof and sleeve 930 may comprise correspondingprotrusion(s) 936 extending radially inwards from an inner diametersurface thereof that extends into groove(s) 954.

With reference to FIG. 22, an exploded view of a lifting device 10 isillustrated, in accordance with various embodiments. Lifting device 10may be a linear jack. Lifting device 10 may generally comprise an outertube 20, a high speed assembly 12, and a low speed assembly 14. Highspeed assembly 12 may generally comprise a screw mechanism comprising arotating nut threadedly coupled to a translating screw, in the manner ofa leadscrew or jack screw. In various embodiments, high speed assembly12 comprises a rotating sleeve 30 (also referred to herein as a highspeed outer sleeve or a first sleeve), and a translating sleeve 40 (alsoreferred to herein as a high speed inner sleeve or a second sleeve). Lowspeed assembly 14 may generally comprise a screw mechanism comprisingthe sleeve 40 of high speed assembly 12 threadedly coupled to an innerscrew that both rotates and translates with respect to the sleeve 40. Inthis regard, low speed assembly 14 may comprise sleeve 40 (also referredto herein as a low speed outer sleeve), and an inner screw 50 (alsoreferred to herein as a low speed inner sleeve). In this regard, sleeve40 may belong to both the high speed assembly 12 and the low speedassembly 14, as described herein in further detail.

Outer tube 20 may comprise a centerline axis 92. Outer tube 20 may behollow. Sleeve 30 may be disposed at least partially within outer tube20. Sleeve 30 may be hollow. Sleeve 40 may be disposed at leastpartially within sleeve 30. Sleeve 40 may be hollow. Inner screw 50 maybe disposed at least partially within sleeve 40. Inner screw 50 may behollow. Lifting device 10 may further comprise a shaft 60. Shaft 60 maybe disposed at least partially within inner screw 50. In this regard,the inner diameter of outer tube 20 may be greater than the outerdiameter of sleeve 30. The inner diameter of sleeve 30 may be greaterthan the outer diameter of sleeve 40. The inner diameter of sleeve 40may be greater than the outer diameter of inner screw 50. The innerdiameter of inner screw 50 may be greater than the outer diameter, orwidth, of shaft 60. Outer tube 20, sleeve 30, sleeve 40, inner screw 50,and shaft 60 are coaxially aligned and/or substantially coaxiallyaligned, though in various embodiments coaxial alignment is not present.One end of shaft 60 may bear a handle 70 which may be used for rotatingthe shaft 60.

Sleeve 30 may be moveable with respect to outer tube 20 between a firstposition (see FIG. 23D) and a second position (see FIG. 23E). In thefirst position, sleeve 30 is drivably coupled to shaft 60. In the secondposition, sleeve 30 is decoupled from shaft 60. In this regard, sleeve30 may further comprise an end plate 32, a first gear 34, and a secondgear 35. First gear 34 may be coupled to, and rotate with, sleeve 30.Second gear 35 may be coupled to, and rotate with, sleeve 30. In variousembodiments, first gear 34 is disposed opposite end plate 32 from secondgear 35. First gear 34 and second gear 35 may be fixed to end plate 32,such as via a weld, a fastener, a threaded connection, or any othersuitable method. In various embodiments, first gear 34 and second gear35 are manufactured separately from end plate 32, though in variousembodiments, first gear 34, second gear 35, and end plate 32 may bemanufactured as a single, monolithic component.

Lifting device 10 may further comprise a gear 65 (also referred toherein as a shaft gear). Shaft gear 65 may be coupled to, and rotatewith, shaft 60. Shaft 60 may drive sleeve 30 via gear 65 in response tosleeve 30 moving to the first position, as described in further detailherein. Gear 65 may be splined to the shaft 60, but gear 65 may also befixedly coupled such as through welding, brazing, a press fit and/or aninterference fit. Gear 65 may comprise any suitable gear, for example, abevel gear or a crown gear. Shaft gear 65 may comprise a plurality ofteeth configured to meshingly engage with a plurality of teeth of firstgear 34. In this manner, rotation of shaft 60 may drive rotation ofsleeve 30, via shaft gear 65 and first gear 34.

Lifting device 10 may further comprise a gear 24 (also referred toherein as an outer tube gear). Gear 24 may be coupled to outer tube 20.Gear 24 may be splined or threaded to the outer tube 20, but gear 24 mayalso be fixedly coupled such as through welding, brazing, a press fitand/or an interference fit. Gear 24 may comprise any suitable gear, forexample, a bevel gear or a crown gear. Gear 24 may comprise a pluralityof teeth configured to meshingly engage with a plurality of teeth ofsecond gear 35. In this manner, sleeve 30 may be locked from rotationwith respect to outer tube 20 in response to second gear 35 meshinglyengaging with gear 24. Second gear 35 may meshingly engage with gear 24in response to sleeve 30 moving to the second position (see FIG. 23E).First gear 34, second gear 35, end plate 32, shaft gear 65, and gear 24may be coaxially aligned with shaft 60.

Lifting device 10 may further comprise a spring 68. Spring 68 may be acoil spring, leaf spring, Belleville spring, or other suitable springfor exerting a bias against sleeve 30. Spring 68 may be operativelycoupled to sleeve 30, to assist movement of sleeve 30 between the firstposition and a second position, as described herein with further detail.In this regard, sleeve 30 may be slidable in the outer tube 20 betweenthe first position and the second position. sleeve 30 may translatealong centerline axis 92 between the first position and the secondposition. The outer tube 20 may comprise an end cap 22. End cap 22 maybe coupled to outer tube 20, e.g., via a threaded connection, fasteners,and/or a metal joining process, such as welding, brazing, etc. End cap22 may comprise a cap structure coupled to the upper end of outer tube20. End cap 22 may comprise a flange extending radially inward from aninner diameter surface of outer tube 20. Shaft 60 may extend through endcap 22. End cap 22 may retain spring 68 within outer tube 20. In thisregard, spring 68 may be compressed between end cap 22 and sleeve 30.More specifically, spring 68 may be compressed between end cap 22 andsecond gear 35 in various embodiments. In various embodiments, gear 24comprises a plurality of teeth configured to engage with second gear 35in response to sleeve 30 moving to the second position (see FIG. 23E).In this manner, sleeve 30 may be restricted from rotating within outertube 20 in the second position.

In various embodiments, sleeve 30 is threadedly coupled to sleeve 40.Thus, rotation of the sleeve 30 causes the sleeve 40 to translate withrespect to outer tube 20. Stated differently, high speed assembly 12translates rotational motion of sleeve 30 to linear motion of sleeve 40.sleeve 40 is threadedly coupled to inner screw 50. Thus, rotation ofinner screw 50 causes the inner screw 50 to translate with respect toouter tube 20 and sleeve 40. Stated differently, low speed assembly 14translates rotational motion of inner screw 50 to linear motion of innerscrew 50.

Shaft 60 may be operatively coupled to inner screw 50 such that innerscrew 50 rotates with shaft 60. In various embodiments, outer surface 62of shaft 60 may comprise a geometry that is complementary to a centeraperture 52 of inner screw 50. In this regard, shaft 60 may interlockwith inner screw 50 to impart rotational forces (i.e., torque)therebetween. In various embodiments, inner screw 50 and shaft 60 arecoupled via a splined connection or the like. However, shaft 60 may beoperatively coupled to inner screw 50 using various methods withoutdeparting from the scope and spirit of the present disclosure, such asvia a fastener, for example.

In operation, rotation of shaft 60 in a first rotational direction,e.g., via handle 70, causes inner screw 50 to rotate with respect outertube 20 and sleeve 40, which in turn causes inner screw 50 to extendfrom sleeve 40 (see FIG. 23B and FIG. 23C). Conversely, rotation ofshaft 60 in a second rotational direction (opposite the first rotationaldirection) causes inner screw 50 to rotate with respect to sleeve 40,which in turn causes inner screw 50 to retract into sleeve 40 (see FIG.23A).

Furthermore, with sleeve 30 in a first position (see FIG. 23A and FIG.23D) with respect to outer tube 20, sleeve 30 may be drivably coupled toshaft 60. Stated differently, rotation of shaft 60 may drive rotation ofsleeve 30. In operation, and with sleeve 30 in the first position withrespect to outer tube 20 and/or gear 65, rotation of shaft 60 in a firstrotational direction, e.g., via handle 70, may cause sleeve 30 to rotatewith respect outer tube 20 and sleeve 40, which in turn causes sleeve 40to extend from sleeve 30. Conversely, rotation of shaft 60 in a secondrotational direction (opposite the first rotational direction) may causesleeve 30 to rotate with respect outer tube 20 and sleeve 40, which inturn causes sleeve 40 to retract into sleeve 30. In the first position,spring 68 may bias first gear 34 of sleeve 30 to engage with shaft gear65. Thus, with the sleeve 30 in the first position, both the sleeve 40and the inner screw 50 are driven to translate with respect to outertube 20 in response to rotation of shaft 60.

However, in operation and with sleeve 30 in a second position (see FIG.23E) with respect to outer tube 20 and/or gear 65, the sleeve 30 isdisengaged from gear 65 (i.e., rotation of shaft 60 and gear 65 does notdrive rotation of sleeve 30 in the disengaged position). In this regard,with sleeve 30 in the second position, rotation of shaft 60 in the firstrotational direction or the second rotational direction may cause onlyinner screw 50 (and not sleeve 30) to rotate with respect to outer tube20, thereby driving only the inner screw 50 to translate. Stateddifferently, the high speed assembly 12 may be disengaged from operationin response to the sleeve 30 moving to the second position. In thismanner, in response to rotation of shaft 60 in the first direction, boththe high speed assembly 12 and the low speed assembly 14 (i.e., thesleeve 40 and inner screw 50) are driven to increase the overall lengthof lifting device 10 but, after reacting force from the ground through,for example, foot 75, rotation of shaft 60 is only imparted to low speedassembly 14 and not high speed assembly 12. With momentary reference toFIG. 23C, as the overall length of lifting device 10 is increased, thefoot 75 of the lifting device 10 may contact a ground surface 402,thereby imparting a force 404 from the ground surface 402 into thesleeve 30 which causes the sleeve 30 to move with respect to outer tube20 against the bias of spring 68 from the first position (i.e., engagedwith gear 65) to the second position (i.e., disengaged from gear 65)thereby decoupling sleeve 30 from torsional forces imparted by shaft 60.In this regard, before the lifting device 10 has contacted a groundsurface, the overall length of the lifting device 10 is quicklyincreased to reduce the overall number of rotations of shaft 60 neededto cause lifting device 10 to reach the ground. In response tocontacting the ground, the high speed assembly 12 is decoupled from theshaft 60 to take advantage of the mechanical advantage of the low speedassembly 14. In this manner, time to operate is reduced relative toconventional designs and increased mechanical advantage is selectivelyactivated.

In various embodiments, sleeve 30 comprises helically extending groovesor threads 31 disposed on an inner diameter surface of sleeve 30. Invarious embodiments, sleeve 40 comprises helically extending grooves orthreads 42 disposed on an outer diameter surface of sleeve 40. Invarious embodiments, sleeve 40 comprises helically extending groovesand/or threads 44 disposed on an inner diameter surface of sleeve 40. Invarious embodiments, inner screw 50 comprises helically extendinggrooves and/or threads 54 disposed on an outer diameter surface of innerscrew 50. Threads 31 are complementary to threads 42, and threads 44 arecomplementary to threads 54. The thread pitch of threads 31, 42 may begreater than the thread pitch of threads 44, 54.

The thread pitch of threads 31, 42 may be between 0.1 millimeters (mm)and 304.8 mm (between 0.0039 inches and 12 inches) in accordance withvarious embodiments, between 1 mm and 101.6 mm (between 0.039 inches and4 inches) in accordance with various embodiments, between 2 mm and 76.2mm (between 0.0787 inches and 3 inches) in accordance with variousembodiments, and/or between 4 mm and 50.8 mm (between 0.157 inches and 2inches) in accordance with various embodiments.

The thread pitch of threads 44, 54 may be between 0.1 millimeters (mm)and 279.4 mm (between 0.0039 inches and 11 inches) in accordance withvarious embodiments, between 1 mm and 25.4 mm (between 0.039 inches and1 inch) in accordance with various embodiments, between 1 mm and 6.35 mm(between 0.039 inches and 0.25 inches) in accordance with variousembodiments, and/or between 2 mm and 3.175 mm (between 0.0787 inches and0.125 inches) in accordance with various embodiments.

In various embodiments, sleeve 40 may be keyed to outer tube 20 toprevent rotation of sleeve 40 with respect to outer tube 20. Forexample, sleeve 40 may comprise one or more axially extending grooves 46(see FIG. 22) disposed in the outer diameter surface thereof and outertube 20 may comprise corresponding protrusion(s) extending radiallyinwards from an inner diameter surface thereof that extends intogroove(s) 46.

With combined reference to FIG. 22, FIG. 24A, and FIG. 24B, foot 75 maybe configured to rotate with respect to inner screw 50, in accordancewith various embodiments. Foot 75 may comprise a sleeve 76 extendingaxially from foot 75. In various embodiments, sleeve 76 is manufacturedas a separate piece from foot 75 wherein sleeve 76 is coupled to foot75, via a fastener 74 for example, though sleeve 76 and foot 75 may bemanufactured as a single, monolithic component. Sleeve 76 may comprise abore 77 configured to receive a bottom end of inner screw 50. Sleeve 76may be secured to the end of inner screw 50 such that sleeve 76 canrotate with respect to inner screw 50. In this manner, inner screw 50may rotate during extension and/or retraction of lifting device 10,while foot 75 remains stationary on a ground surface. In variousembodiments, a pin 56 may be disposed to extend through inner screw 50after inner screw 50 is place within sleeve 76. Pin 56 may extend atleast partially into a cylindrical groove disposed in the bore 77 toprevent inner screw 50 from pulling out bore 77, while simultaneouslyallowing rotating of inner screw 50 with respect to sleeve 76. Invarious embodiments, a bearing 72 may be disposed between inner screw 50and sleeve 76 for facilitating rotation of inner screw 50 with respectto sleeve 76. Bearing 72 may comprise a ball bearing, a thrust needlebearing, among other types of bearings. In various embodiments, a greasefitting 79 may be coupled to sleeve 76. Grease fitting 79 may be removedto install and/or remove pin 56. Grease fitting 79 may be in fluidcommunication with bearing 72. In this manner, grease may be moved intobore 77 and/or cylindrical groove 78 via grease fitting 79.

In various embodiments, shaft 60 may be a two-piece telescoping shaft 61comprising a first shaft 64 and a second shaft 66 configured fortelescoping expansion and contraction along the longitudinal axis. FIG.26A and FIG. 26B depict lifting device 10 in a retracted position andcomprising the two-piece telescoping shaft 61. FIG. 26C and FIG. 26Ddepict lifting device 10 in an extended position and comprising thetwo-piece telescoping shaft 61. It can be seen that lifting device 10may comprise a larger range of extension with the two-piece telescopingshaft 61 in comparison to a single piece shaft 60 (see FIG. 23B and FIG.23C). In this manner, by equipping lifting device 10 with a two-pieceshaft 61, the total length of the lifting device 10 is minimized in theretracted position and maximized in the fully extended position.

With reference to FIG. 26C, the top end of inner screw 50 may comprise aflange 58 extending radially inward from the radially inner surface ofinner screw 50. Second shaft 66 may interface with inner screw 50 viaflange 58. In various embodiments, the bottom end of second shaft 66 maycomprise an aperture 67 extending transversely through second shaft 66for receiving a pin for retaining the bottom end of second shaft 66within inner screw 50. In this manner, the second shaft 66 is preventedfrom pulling completely out of the inner screw 50.

In various embodiments, the top end of second shaft 66 may similarlycomprise a flange 59 extending radially inward from the radially innersurface of second shaft 66. First shaft 64 may interface with secondshaft 66 via flange 59. In various embodiments, the bottom end of firstshaft 64 may similarly comprise an aperture 63 extending transverselythrough first shaft 64 for receiving a pin for retaining the bottom endof first shaft 64 within second shaft 66. In this manner, the firstshaft 64 is prevented from pulling completely out of the second shaft66.

With reference to FIG. 27, a flow chart of a method 80 of assembling alifting device, such as a linear jack, is illustrated, in accordancewith various embodiments. Method 80 includes coupling an inner sleeve toan outer sleeve, wherein the inner sleeve is disposed at least partiallywithin the outer sleeve (step 81). Method 80 includes coupling an innerscrew to the inner sleeve, wherein the inner screw is disposed at leastpartially within the inner sleeve (step 82). Method 80 includes couplinga shaft to the inner screw (step 83).

With combined reference to FIG. 22 and FIG. 27, step 81 may includethreading sleeve 40 into sleeve 30. Step 82 may include threading innerscrew 50 into sleeve 40. Step 83 may include coupling shaft 60 to innerscrew 50. Shaft 60 may be disposed to extend at least partially throughsleeve 30, sleeve 40, and inner screw 50.

With combined reference to FIG. 28A and FIG. 28B, a side view and asection view, respectively, of a lifting device 1100 is illustrated, inaccordance with various embodiments. Lifting device 1100 may be a linearjack. Lifting device 1100 may operate similar to lifting device 200,except that translating screw 1150 is received by shaft 1160.Furthermore, lifting device 1100 comprises a sleeve 1155 (also referredto herein as a cover sleeve) attached to translating screw 1150. Sleeve1155 may be affixed to translating screw 1150. In this regard, sleeve1155 may be configured to translate together with translating screw 1150with respect to sleeve 1140. Sleeve 1155 may be keyed to an adjacentcomponent to prevent rotation of sleeve 1155 and translating screw 1150.Sleeve 1155 may protect translating screw 1150 from ambient elementssuch as dust, water, etc., thereby increasing the life and robustness oflifting device 1100. Sleeve 1155 may also at least partially containlubricants, thus tending to retain lubricants on or in close proximityto translating screw 1150.

Lifting device 1100 may generally comprise an outer tube 1110. Outertube 1110 may comprise a centerline axis 1192. Outer tube 1110 may behollow. A high speed assembly comprising a first sleeve 1120 (alsoreferred to herein as a high speed outer sleeve or a first outer sleeve)threadedly coupled to a second sleeve 1130 (also referred to herein as ahigh speed inner sleeve) may be disposed at least partially within outertube 1110. Said high speed assembly may generally comprise a screwmechanism comprising a rotating nut threadedly coupled to a translatingscrew, in the manner of a leadscrew or jack screw. First sleeve 1120 maybe hollow. First sleeve 1120 may be threaded on its inner diametersurface. First sleeve 1120 may comprise a hollow cylinder. Second sleeve1130 may be disposed at least partially within first sleeve 1120. Secondsleeve 1130 may be hollow. Second sleeve 1130 may comprise a hollowcylinder. Second sleeve 1130 may be threaded on its outer diametersurface.

A low speed assembly comprising sleeve 1140 (also referred to herein asa low speed outer sleeve, a first sleeve, a third sleeve, and/or anouter sleeve) threadedly coupled to a translating screw 1150 may bedisposed at least partially within outer tube 1110. Said low speedassembly may generally comprise a screw mechanism comprising a rotatingnut threadedly coupled to a translating screw, in the manner of aleadscrew or jack screw. Said low speed assembly may be disposed atleast partially within second sleeve 1130.

Although the present disclosure is described in accordance with variousembodiments on the basis of a screw mechanism having a rotating nut anda translating screw, it should be understood that the present disclosurecan be applied with a rotating screw and a translating nut.

Third sleeve 1140 may be disposed at least partially within secondsleeve 1130. Third sleeve 1140 may be hollow. Translating screw 1150 maybe disposed at least partially within third sleeve 1140. Translatingscrew 1150 may be solid. Stated differently, translating screw 1150 maycomprise a solid rod with helically extending threads disposed on theouter diameter surface thereof. Lifting device 1100 may further comprisea shaft 1160. Shaft 1160 may comprise a hollow portion. Translatingscrew 1150 may be received into the hollow portion of shaft 1160. Thirdsleeve 1140 may receive shaft 1160. In this regard, third sleeve 1140may surround shaft 1160.

In this regard, the inner diameter of outer tube 1110 may be greaterthan the outer diameter of first sleeve 1120. The inner diameter offirst sleeve 1120 may be greater than the outer diameter of secondsleeve 1130. The inner diameter of second sleeve 1130 may be greaterthan the outer diameter of third sleeve 1140. The inner diameter ofthird sleeve 1140 may be greater than the outer diameter of translatingscrew 1150. The inner diameter of third sleeve 1140 may be greater thanthe outer diameter of shaft 1160. The inner diameter of shaft 1160 maybe greater than the outer diameter of translating screw 1150. Outer tube1110, first sleeve 1120, second sleeve 1130, third sleeve 1140,translating screw 1150, and shaft 1160 may be coaxially aligned.

Lifting device 1100 may further comprise a gear 1165. Gear 1165 may becoupled to, and rotate with, shaft 1160. Gear 1165 may be coaxiallyaligned with shaft 1160. Shaft 1160 may drive first sleeve 1120 via gear1165 in response to first sleeve 1120 moving to a first position (seeFIG. 28B), as described in further detail herein. Gear 1165 may besplined to the shaft 1160 but gear 1165 may also be fixedly coupled suchas through welding, brazing, a press fit and/or an interference fit.Gear 1165 may comprise any suitable gear, for example, a bevel gear or acrown gear.

Lifting device 1100 may further comprise a spring 1106. Spring 1106 maybe a coil spring, leaf spring, Belleville spring, or other suitablespring for exerting a bias against first sleeve 1120. Spring 1106 may beoperatively coupled to first sleeve 1120, to assist movement of firstsleeve 1120 between the first position (see FIG. 28B) and a secondposition (see FIG. 28D), as described herein with further detail. Inthis regard, first sleeve 1120 may be slidable in the outer tube 1110between the first position and the second position. First sleeve 1120may translate along centerline axis 1192 between the first position andthe second position. The outer tube 1110 may comprise a retaining member1112. Retaining member 1112 may be coupled to outer tube 1110, e.g., viaa threaded connection, fasteners, and/or a metal joining process, suchas welding, brazing, etc. Retaining member 1112 may comprise a capstructure coupled to the upper end of outer tube 1110. Retaining member1112 may comprise a flange extending radially inward from outer tube1110. Shaft 1160 may extend through retaining member 1112. Retainingmember 1112 may retain spring 1106 within outer tube 1110. In thisregard, spring 1106 may be compressed between retaining member 1112 andfirst sleeve 1120. In various embodiments, retaining member 1112comprises a mating surface 1114 configured to engage with a matingsurface 1124 of first sleeve 1120 in response to first sleeve 1120moving to the second position (see FIG. 28D). In this manner, firstsleeve 1120 may be restricted from rotating within outer tube 1110 inthe second position. In various embodiments, and as shown, matingsurface 1124 and mating surface 1114 are crenulated and, as shown,having crenulations that are complementary to one another. Thecrenulations interact, in response to axial compression, to transfertorque to first sleeve 1120

In various embodiments, first sleeve 1120 is threadedly coupled tosecond sleeve 1130. Thus, rotation of the first sleeve 1120 causes thesecond sleeve 1130 to translate with respect to outer tube 1110. Stateddifferently, the high speed assembly translates rotational motion offirst sleeve 1120 to linear motion of second sleeve 1130. In variousembodiments, third sleeve 1140 is threadedly coupled to translatingscrew 1150. In various embodiments, third sleeve 1140 is threadedlycoupled to translating screw 1150 at a bottom end 1144 of the thirdsleeve 1140. In this regard, third sleeve 1140 may comprise a flange1148 extending radially inward and disposed at the bottom end 1144thereof whereby translating screw 1150 is threadedly coupled to thirdsleeve 1140. Thus, rotation of the third sleeve 1140 causes thetranslating screw 1150 to translate with respect to outer tube 1110.Stated differently, the low speed assembly translates rotational motionof third sleeve 1140 to linear motion of translating screw 1150.

Shaft 1160 may be operatively coupled to third sleeve 1140 such thatthird sleeve 1140 rotates with shaft 1160. Shaft 1160 may be operativelycoupled to third sleeve 1140 via a keyed connection, e.g., a splinedconnection or the like, at an upper end of third sleeve 1140. In variousembodiments, shaft 1160 may comprise one or more splines 1162 and thirdsleeve 1140 may comprise a center aperture 1142 comprising a geometrythat is complementary to shaft 1160. In this regard, center aperture1142 may comprise one or more grooves configured to receive the one ormore splines 1162 of shaft 1160 such that shaft 1160 interlocks withthird sleeve 1140 to impart rotational forces (i.e., torque)therebetween. Stated differently, third sleeve 1140 and shaft 1160 maybe coupled via a splined connection. Third sleeve 1140 may be drivablycoupled to shaft 1160 via center aperture 1142. Center aperture 1142 maycomprise various geometries, such as triangular, star, circular, square,or any other geometry that interlocks shaft 1160 with third sleeve 1140.However, shaft 1160 may be operatively coupled to third sleeve 1140using various methods without departing from the scope and spirit of thepresent disclosure.

In operation, rotation of shaft 1160 in a first rotational direction,e.g., via handle 1170, causes third sleeve 1140 to rotate with respectouter tube 1110 and translating screw 1150, which in turn causestranslating screw 1150 to extend from third sleeve 1140 (see FIG. 28Cand FIG. 28D). Conversely, rotation of shaft 1160 in a second rotationaldirection (opposite the first rotational direction) causes third sleeve1140 to rotate with respect outer tube 1110 and translating screw 1150,which in turn causes translating screw 1150 to retract into third sleeve1140 (see FIG. 28A and FIG. 28B).

Furthermore, with first sleeve 1120 in a first position (see FIG. 28B)with respect to outer tube 1110, first sleeve 1120 may be drivablycoupled to shaft 1160. Stated differently, rotation of shaft 1160 maydrive rotation of first sleeve 1120. In operation, and with first sleeve1120 in the first position with respect to outer tube 1110 and/or gear1165, rotation of shaft 1160 in a first rotational direction, e.g., viahandle 1170, may cause first sleeve 1120 to rotate with respect outertube 1110 and second sleeve 1130, which in turn causes second sleeve1130 to extend from first sleeve 1120. Conversely, rotation of shaft1160 in a second rotational direction (opposite the first rotationaldirection) may cause first sleeve 1120 to rotate with respect outer tube1110 and second sleeve 1130, which in turn causes second sleeve 1130 toretract into first sleeve 1120. In the first position, spring 1106 maybias first sleeve 1120 to engage with gear 1165. Thus, with the firstsleeve 1120 in the first position, both the second sleeve 1130 and thetranslating screw 1150 are driven to translate with respect to outertube 1110 in response to rotation of shaft 1160.

However, with combined reference to FIG. 28C and FIG. 28D, in operationand with first sleeve 1120 in the second position with respect to outertube 1110 and/or gear 1165, the first sleeve 1120 is disengaged fromgear 1165 (i.e., rotation of shaft 1160 and gear 1165 does not driverotation of first sleeve 1120 in the disengaged position). In thisregard, with first sleeve 1120 in the second position, rotation of shaft1160 in the first rotational direction or the second rotationaldirection may cause only third sleeve 1140 (and not first sleeve 1120)to rotate with respect to outer tube 1110 and translating screw 1150,thereby driving only the translating screw 1150 to translate. Stateddifferently, the high speed assembly (i.e., the first sleeve 1120 andsecond sleeve 1130) may be disengaged from operation in response to thefirst sleeve 1120 moving to the second position. In this manner, inresponse to rotation of shaft 1160 in the first direction, both the highspeed assembly and the low speed assembly (i.e., the third sleeve 1140and translating screw 1150) are driven to increase the overall length oflifting device 1100 but, after reacting force from the ground through,for example, foot 1175, rotation of shaft 1160 is only imparted to thelow speed assembly and the not high speed assembly. As the overalllength of lifting device 1100 is increased, the foot 1175 of the liftingdevice 1100 may contact a ground surface—e.g., as described in furtherdetail with respect to FIG. 4E and FIG. 4F—thereby imparting a forcefrom the ground surface into the first sleeve 1120 which causes thefirst sleeve 1120 to move with respect to outer tube 1110 against thebias of spring 1106 from the first position (i.e., engaged with gear1165) to the second position (i.e., disengaged from gear 1165) therebydecoupling first sleeve 1120 from torsional forces imparted by shaft1160. In this regard, before the lifting device 1100 has contacted aground surface, the overall length of the lifting device 1100 is quicklyincreased to reduce the overall number of rotations of shaft 1160 neededto cause lifting device 1100 to reach the ground. In response tocontacting the ground, the high speed assembly is decoupled from theshaft 1160 to take advantage of the mechanical advantage of the lowspeed assembly. In this manner, time to operate is reduced relative toconventional designed and increased mechanical advantage is selectivelyactivated.

With reference to FIG. 29A, a section view of an upper portion oflifting device 1100 is illustrated, in accordance with variousembodiments. In various embodiments, second sleeve 1130 compriseshelically extending grooves or threads 1132. In various embodiments,translating screw 1150 comprises helically extending grooves and/orthreads 1152. The thread pitch of threads 1132 may be greater than thethread pitch of threads 1152. Stated differently, translating screw 1150may comprise more threads per inch (TPI) than second sleeve 1130. Inthis manner, the high speed assembly translates further and faster perrotation of shaft 1160 than the low speed assembly, causing the liftingdevice 1100 to reach a ground surface faster than if the high speedassembly were not present. Furthermore, in response to the liftingdevice 1100 contacting a ground surface and the high speed assemblydisengaging from the shaft 1160, the reduced thread pitch of the lowspeed assembly takes advantage of the reduced torque required forextending the lifting device 1100.

In various embodiments, second sleeve 1130 comprises a first flange 1137extending radially inward therefrom. First flange 1137 may be disposedat an upper end of the second sleeve 1130. First flange 1137 may bedisposed at an upper terminus of the second sleeve 1130. In variousembodiments, first flange 1137 is removably coupled to second sleeve1130. Second sleeve 1130 may comprise a second flange 1138 extendingradially inward therefrom. Second flange 1138 may be disposed axiallyfrom the first flange 1137. Third sleeve 1140 may comprise a flange 1146extending radially outward therefrom. Flange 1146 may be disposed at anupper end of the third sleeve 1140. Flange 1146 may be disposed at anupper terminus of the third sleeve 1140. Flange 1146 may be capturedbetween the first flange 1136 and the second flange 1138. Flange 1146may be configured to transfer axial loads between third sleeve 1140 andsecond sleeve 1130 via first flange 1136 and second flange 1138.

In various embodiments, a bearing 1108 may be disposed between flange1146 and first flange 1137. Bearing 1108 may reduce friction betweensecond sleeve 1130 and third sleeve 1140. Bearing 1108 may assistrotation of third sleeve 1140 with respect to second sleeve 1130.Bearing 1108 may comprise a thrust needle roller bearing or the like, inaccordance with various embodiments.

With reference to FIG. 29B, a section view of a lower portion of liftingdevice 1100 is illustrated, in accordance with various embodiments.Second sleeve 1130 may be keyed to outer tube 1110 to prevent rotationof second sleeve 1130 with respect to outer tube 1110. For example,second sleeve 1130 may comprise one or more axially extending grooves1134 disposed in the outer diameter surface thereof and outer tube 1110may comprise corresponding protrusion(s) 1116 extending radially inwardsfrom an inner diameter surface thereof that extends into groove(s) 1134.

In various embodiments, sleeve 1155 may be affixed to the bottom end1154 of translating screw 1150. In this regard, sleeve 1155 andtranslating screw 1150 may move together. Sleeve 1155 may be keyed tosecond sleeve 1130 to prevent rotation of sleeve 1155 and translatingscrew 1150 with respect to second sleeve 1130. For example, sleeve 1155may comprise one or more axially extending grooves 1157 disposed in theouter diameter surface thereof and second sleeve 1130 may comprisecorresponding protrusion(s) 1136 extending radially inwards from aninner diameter surface thereof that extends into groove(s) 1157.

Sleeve 1155 may protect translating screw 1150 from ambient elementssuch as dust, water, etc., thereby increasing the life and robustness oflifting device 1100. Stated differently, translating screw 1150 may beenclosed within sleeve 1155. Sleeve 1155 may comprise a hollow cylinder.Third sleeve 1140 may be at least partially disposed within sleeve 1155.

With reference to FIG. 30, a section view of a bottom portion of liftingdevice 1100 with the outer tube, sleeve, and sleeve omitted for claritypurposes is illustrated, in accordance with various embodiments. Stateddifferently, the high speed assembly and outer tube are omitted in FIG.30. Translating screw 1150 may comprise a flange 1151 extending from thebottom end thereof. Sleeve 1155 may be coupled to flange 1151. In thismanner, sleeve 1155 may be radially spaced apart from translating screw1150. In various embodiments, translating screw 1150 and flange 1151comprise a single, monolithic piece of material. translating screw 1150and sleeve 1155 may be coupled to foot 1175. Sleeve 1155 may be madefrom a metal or metal alloy, such as cast iron, steel, stainless steel,austenitic stainless steels, ferritic stainless steels, martensiticstainless steels, titanium, titanium alloys, aluminum, aluminum alloys,galvanized steel, or any other suitable metal or metal alloy. Sleeve1155 may be made from a fiber-reinforced composite material.

With reference to FIG. 31, a flow chart of a method 1200 of assembling alifting device, such as a linear jack, is illustrated, in accordancewith various embodiments. Method 1200 includes disposing a second sleeveat least partially within a first sleeve (step 1210). Method 1200includes disposing a translating screw at least partially within a thirdsleeve (step 1220). Method 1200 includes disposing the third sleeve atleast partially within the second sleeve (step 1230). Method 1200includes coupling a cover sleeve to the translating screw (step 1240).

With combined reference to FIG. 28B and FIG. 31, step 1210 may includethreading second sleeve 1130 into first sleeve 1120. Step 1220 mayinclude threading translating screw 1150 into third sleeve 1140. Step1230 may include moving third sleeve 1140 into second sleeve 1130. Step1230 may include coupling third sleeve 1140 in keyed connection withsecond sleeve 1130. Step 1240 may include coupling sleeve 1155 totranslating screw 1150, such as via a fastener, a metal joining process,a threaded connection, or any other suitable coupling. Sleeve 1155 iscoupled to translating screw 1150 such that sleeve 1155 surroundstranslating screw 1150. Sleeve 1155 may be disposed to surround thirdsleeve 1140. Sleeve 1155 may be coupled in keyed connection with secondsleeve 1130.

Benefits and other advantages have been described herein with regard tospecific embodiments. Furthermore, the connecting lines shown in thevarious figures contained herein are intended to represent examplefunctional relationships and/or physical couplings between the variouselements. It should be noted that many alternative or additionalfunctional relationships or physical connections may be present in apractical system. However, the benefits, advantages, and any elementsthat may cause any benefit or advantage to occur or become morepronounced are not to be construed as critical, required, or essentialfeatures or elements of the disclosure. The scope of the disclosure isaccordingly to be limited by nothing other than the appended claims, inwhich reference to an element in the singular is not intended to mean“one and only one” unless explicitly so stated, but rather “one ormore.” Moreover, where a phrase similar to “at least one of A, B, or C”is used in the claims, it is intended that the phrase be interpreted tomean that A alone may be present in an embodiment, B alone may bepresent in an embodiment, C alone may be present in an embodiment, orthat any combination of the elements A, B and C may be present in asingle embodiment; for example, A and B, A and C, B and C, or A and Band C.

Systems, methods and apparatus are provided herein. In the detaileddescription herein, references to “various embodiments”, “oneembodiment”, “an embodiment”, “an example embodiment”, etc., indicatethat the embodiment described may include a particular feature,structure, or characteristic, but every embodiment may not necessarilyinclude the particular feature, structure, or characteristic. Moreover,such phrases are not necessarily referring to the same embodiment.Further, when a particular feature, structure, or characteristic isdescribed in connection with an embodiment, it is submitted that it iswithin the knowledge of one skilled in the art to affect such feature,structure, or characteristic in connection with other embodimentswhether or not explicitly described. After reading the description, itwill be apparent to one skilled in the relevant art(s) how to implementthe disclosure in alternative embodiments.

Furthermore, no element, component, or method step in the presentdisclosure is intended to be dedicated to the public regardless ofwhether the element, component, or method step is explicitly recited inthe claims. No claim element is intended to invoke 35 U.S.C. 112(f)unless the element is expressly recited using the phrase “means for.” Asused herein, the terms “comprises”, “comprising”, or any other variationthereof, are intended to cover a non-exclusive inclusion, such that aprocess, method, article, or apparatus that comprises a list of elementsdoes not include only those elements but may include other elements notexpressly listed or inherent to such process, method, article, orapparatus.

What is claimed is:
 1. A linear jack, comprising: a first sleeve; asecond sleeve disposed at least partially within the first sleeve,wherein the first sleeve is threadedly coupled to the second sleeve; athird sleeve disposed at least partially within the second sleeve; atranslating screw disposed at least partially within the third sleeve,wherein the third sleeve is threadedly coupled to the translating screw;a cover sleeve coupled to the translating screw; an outer tubecomprising a centerline axis, wherein the first sleeve is disposed atleast partially within the outer tube; a shaft coupled to the thirdsleeve; a gear coupled to the shaft; and a spring operatively coupled tothe first sleeve; wherein the first sleeve is slidable in the outer tubebetween a first position and a second position; the third sleeve isconfigured to rotate with the shaft, the gear is disposed within thefirst sleeve, and the spring is disposed within the outer tube; thetranslating screw is disposed at least partially within the coversleeve; the cover sleeve is configured to translate with the translatingscrew; and wherein: in the first position, the spring biases the firstsleeve to engage the gear whereby turning the shaft a first rotationaldirection extends the second sleeve from the first sleeve, and turningthe shaft a second rotational direction retracts the second sleeve intothe first sleeve; and in the second position, the first sleeve is movedagainst a bias of the spring and disengaged from the gear wherebyturning the shaft the first rotational direction extends the translatingscrew from the third sleeve, and turning the shaft the second rotationaldirection retracts the translating screw into the third sleeve.
 2. Thelinear jack of claim 1, wherein the cover sleeve is disposed at leastpartially within the second sleeve.
 3. The linear jack of claim 2,wherein the cover sleeve is keyed to the second sleeve.
 4. The linearjack of claim 1, wherein the second sleeve is configured to translatewith respect to the first sleeve in response to rotation of the firstsleeve, and the translating screw is configured to translate withrespect to the third sleeve in response to rotation of the third sleeve.5. The linear jack of claim 1, wherein a thread pitch of the secondsleeve is greater than a thread pitch of the translating screw.
 6. Thelinear jack of claim 1, wherein turning the shaft the first rotationaldirection extends the translating screw from the third sleeve, andturning the shaft the second rotational direction retracts thetranslating screw into the third sleeve, regardless of the first sleevebeing in the first position or the second position.
 7. The linear jackof claim 1, wherein the first sleeve, the second sleeve, the thirdsleeve, and the translating screw are in coaxial alignment.
 8. Thelinear jack of claim 1, further comprising a foot coupled to an end ofthe translating screw.
 9. A method of manufacturing a linear jack,comprising: disposing a first sleeve at least partially within an outertube, the outer tube comprising a centerline axis; disposing a secondsleeve at least partially within the first sleeve, wherein the firstsleeve is threadedly coupled to the second sleeve; disposing atranslating screw at least partially within a third sleeve, wherein thethird sleeve is threadedly coupled to the translating screw; disposingthe third sleeve at least partially within the second sleeve; coupling ashaft to the third sleeve; coupling a gear to the shaft; operativelycoupling a spring to the first sleeve; and coupling a cover sleeve tothe translating screw; wherein the first sleeve is slidable in the outertube between a first position and a second position; the third sleeve isconfigured to rotate with the shaft, the gear is disposed within thefirst sleeve, and the spring is disposed within the outer tube; thetranslating screw is disposed at least partially within the coversleeve; the cover sleeve is configured to translate with the translatingscrew; and wherein: in the first position, the spring biases the firstsleeve to engage the gear whereby turning the shaft a first rotationaldirection extends the second sleeve from the first sleeve, and turningthe shaft a second rotational direction retracts the second sleeve intothe first sleeve; and in the second position, the first sleeve is movedagainst a bias of the spring and disengaged from the gear wherebyturning the shaft the first rotational direction extends the translatingscrew from the third sleeve, and turning the shaft the second rotationaldirection retracts the translating screw into the third sleeve.
 10. Themethod of claim 9, further comprising: disposing the cover sleeve tosurround the translating screw; disposing the cover sleeve to surroundthe third sleeve; and disposing the cover sleeve in keyed connectionwith the second sleeve.